Differentiation of human embryonic stem cells

ABSTRACT

The present invention provides methods to promote the differentiation of pluripotent stem cells and the products related to or resulting from such methods. In particular, the present invention provides an improved method for the formation of pancreatic hormone expressing cells and pancreatic hormone secreting cells. In addition, the present invention also provides methods to promote the differentiation of pluripotent stem cells without the use of a feeder cell layer and the products related to or resulting from such methods. The present invention also provides methods to promote glucose-stimulated insulin secretion in insulin-producing cells derived from pluripotent stem cells.

CROSS-REFERENCE TO RELATED APPLICATIONS

This is a continuation of U.S. patent application Ser. No. 16/586,786,filed on Sep. 27, 2019, which is continuation of U.S. patent applicationSer. No. 15/978,935, filed May 14, 2018, issued as U.S. Pat. No.10,494,609, which is a continuation of U.S. patent application Ser. No.14/719,124, filed May 21, 2015, issued as U.S. Pat. No. 9,969,982, whichis a divisional of U.S. patent application Ser. No. 12/277,904, filedNov. 25, 2008, issued as U.S. Pat. No. 9,062,290, which claims thebenefit of U.S. Provisional Patent Application No. 60/990,529, filedNov. 27, 2007, the contents of all of which are incorporated byreference in their entireties.

FIELD OF THE INVENTION

The present invention provides methods to promote the differentiation ofpluripotent stem cells and the products related to or resulting fromsuch methods. In particular, the present invention provides an improvedmethod for the formation of pancreatic hormone expressing cells andpancreatic hormone secreting cells. In addition, the present inventionalso provides methods to promote the differentiation of pluripotent stemcells without the use of a feeder cell layer and the products related toor resulting from such methods. The present invention also providesmethods to promote glucose-stimulated insulin secretion ininsulin-producing cells derived from pluripotent stem cells.

BACKGROUND

Advances in cell-replacement therapy for Type I diabetes mellitus and ashortage of transplantable islets of Langerhans have focused interest ondeveloping sources of insulin-producing cells, or 13 cells, appropriatefor engraftment. One approach is the generation of functional 13 cellsfrom pluripotent stem cells, such as, for example, embryonic stem cells.

In vertebrate embryonic development, a pluripotent cell gives rise to agroup of cells comprising three germ layers (ectoderm, mesoderm, andendoderm) in a process known as gastrulation. Tissues such as, forexample, thyroid, thymus, pancreas, gut, and liver, will develop fromthe endoderm, via an intermediate stage. The intermediate stage in thisprocess is the formation of definitive endoderm. Definitive endodermcells express a number of markers, such as, HNF-3beta, GATA4, Mix11,CXCR4 and Sox-17.

Pluripotent stem cells may express one or more of the stage-specificembryonic antigens (SSEA) 3 and 4, and markers detectable usingantibodies designated Tra-1-60 and Tra-1-81 (Thomson et al., Science282:1145, 1998). Differentiation of pluripotent stem cells in vitroresults in the loss of SSEA-4, Tra-1-60, and Tra-1-81 expression (ifpresent) and increased expression of SSEA-1. Undifferentiatedpluripotent stem cells typically have alkaline phosphatase activity,which can be detected by fixing the cells with 4% paraformaldehyde, andthen developing with Vector Red as a substrate, as described by themanufacturer (Vector Laboratories, Burlingame Calif.). Undifferentiatedpluripotent stem cells also typically express Oct-4 and TERT, asdetected by RT-PCR.

Pluripotent stem cells are typically cultured on a layer of feeder cellsthat support the pluripotent stem cells in various ways. Alternatively,pluripotent stem cells are cultured in a culture system that isessentially free of feeder cells, but nonetheless supports proliferationof pluripotent stem cells without undergoing substantialdifferentiation. The growth of pluripotent stem cells in feeder-freeculture without differentiation is supported using a medium conditionedby culturing previously with another cell type. Alternatively, thegrowth of pluripotent stem cells in feeder-free culture withoutdifferentiation is supported using a chemically defined medium.

For example, Reubinoff et al. (Nature Biotechnology 18: 399-404 (2000))and Thompson et al. (Science 6 Nov. 1998: Vol. 282. no. 5391, pp.1145-1147) disclose the culture of pluripotent stem cell lines fromhuman blastocysts using a mouse embryonic fibroblast feeder cell layer.

Richards et al., (Stem Cells 21: 546-556, 2003) evaluated a panel of 11different human adult, fetal and neonatal feeder cell layers for theirability to support human pluripotent stem cell culture. Richards et al.,states: “human embryonic stem cell lines cultured on adult skinfibroblast feeders retain human embryonic stem cell morphology andremain pluripotent”.

US20020072117 discloses cell lines that produce media that support thegrowth of primate pluripotent stem cells in feeder-free culture. Thecell lines employed are mesenchymal and fibroblast-like cell linesobtained from embryonic tissue or differentiated from embryonic stemcells. US20020072117 also discloses the use of the cell lines as aprimary feeder cell layer.

In another example, Wang et al. (Stem Cells 23: 1221-1227, 2005)discloses methods for the long-term growth of human pluripotent stemcells on feeder cell layers derived from human embryonic stem cells.

In another example, Stojkovic et al. (Stem Cells 2005 23: 306-314, 2005)disclose a feeder cell system derived from the spontaneousdifferentiation of human embryonic stem cells.

In a further example, Miyamoto et al. (Stem Cells 22: 433-440, 2004)disclose a source of feeder cells obtained from human placenta.

Amit et al. (Biol. Reprod 68: 2150-2156, 2003) discloses a feeder celllayer derived from human foreskin.

In another example, Inzunza et al. (Stem Cells 23: 544-549, 2005)disclose a feeder cell layer from human postnatal foreskin fibroblasts.

U.S. Pat. No. 6,642,048 discloses media that support the growth ofprimate pluripotent stem (pPS) cells in feeder-free culture, and celllines useful for production of such media. U.S. Pat. No. 6,642,048states: “This invention includes mesenchymal and fibroblast-like celllines obtained from embryonic tissue or differentiated from embryonicstem cells. Methods for deriving such cell lines, processing media, andgrowing stem cells using the conditioned media are described andillustrated in this disclosure.”

In another example, WO2005014799 discloses conditioned medium for themaintenance, proliferation and differentiation of mammalian cells.WO2005014799 states: “The culture medium produced in accordance with thepresent invention is conditioned by the cell secretion activity ofmurine cells, in particular, those differentiated and immortalizedtransgenic hepatocytes, named MMH (Met Murine Hepatocyte).”

In another example, Xu et al. (Stem Cells 22: 972-980, 2004) disclosesconditioned medium obtained from human embryonic stem cell derivativesthat have been genetically modified to over express human telomerasereverse transcriptase.

In another example, US20070010011 discloses a chemically defined culturemedium for the maintenance of pluripotent stem cells.

An alternative culture system employs serum-free medium supplementedwith growth factors capable of promoting the proliferation of embryonicstem cells. For example, Cheon et al. (BioReprodDOI:10.1095/biolreprod.105.046870, Oct. 19, 2005) disclose afeeder-free, serum-free culture system in which embryonic stem cells aremaintained in unconditioned serum replacement (SR) medium supplementedwith different growth factors capable of triggering embryonic stem cellself-renewal.

In another example, Levenstein et al. (Stem Cells 24: 568-574, 2006)disclose methods for the long-term culture of human embryonic stem cellsin the absence of fibroblasts or conditioned medium, using mediasupplemented with bFGF.

In another example, US20050148070 discloses a method of culturing humanembryonic stem cells in defined media without serum and withoutfibroblast feeder cells, the method comprising: culturing the stem cellsin a culture medium containing albumin, amino acids, vitamins, minerals,at least one transferrin or transferrin substitute, at least one insulinor insulin substitute, the culture medium essentially free of mammalianfetal serum and containing at least about 100 ng/ml of a fibroblastgrowth factor capable of activating a fibroblast growth factor signalingreceptor, wherein the growth factor is supplied from a source other thanjust a fibroblast feeder layer, the medium supported the proliferationof stem cells in an undifferentiated state without feeder cells orconditioned medium.

In another example, US20050233446 discloses a defined media useful inculturing stem cells, including undifferentiated primate primordial stemcells. In solution, the media is substantially isotonic as compared tothe stem cells being cultured. In a given culture, the particular mediumcomprises a base medium and an amount of each of bFGF, insulin, andascorbic acid necessary to support substantially undifferentiated growthof the primordial stem cells.

In another example, U.S. Pat. No. 6,800,480 states “In one embodiment, acell culture medium for growing primate-derived primordial stem cells ina substantially undifferentiated state is provided which includes a lowosmotic pressure, low endotoxin basic medium that is effective tosupport the growth of primate-derived primordial stem cells. The basicmedium is combined with a nutrient serum effective to support the growthof primate-derived primordial stem cells and a substrate selected fromthe group consisting of feeder cells and an extracellular matrixcomponent derived from feeder cells. The medium further includesnon-essential amino acids, an anti-oxidant, and a first growth factorselected from the group consisting of nucleosides and a pyruvate salt.”

In another example, US20050244962 states: “In one aspect the inventionprovides a method of culturing primate embryonic stem cells. Onecultures the stem cells in a culture essentially free of mammalian fetalserum (preferably also essentially free of any animal serum) and in thepresence of fibroblast growth factor that is supplied from a sourceother than just a fibroblast feeder layer. In a preferred form, thefibroblast feeder layer, previously required to sustain a stem cellculture, is rendered unnecessary by the addition of sufficientfibroblast growth factor.”

In a further example, WO2005065354 discloses a defined, isotonic culturemedium that is essentially feeder-free and serum-free, comprising: a. abasal medium; b. an amount of bFGF sufficient to support growth ofsubstantially undifferentiated mammalian stem cells; c. an amount ofinsulin sufficient to support growth of substantially undifferentiatedmammalian stem cells; and d. an amount of ascorbic acid sufficient tosupport growth of substantially undifferentiated mammalian stem cells.

In another example, WO2005086845 discloses a method for maintenance ofan undifferentiated stem cell, said method comprising exposing a stemcell to a member of the transforming growth factor-beta (TGFβ) family ofproteins, a member of the fibroblast growth factor (FGF) family ofproteins, or nicotinamide (NIC) in an amount sufficient to maintain thecell in an undifferentiated state for a sufficient amount of time toachieve a desired result.

Pluripotent stem cells may be cultured and differentiated on a tissueculture substrate coated with an extracellular matrix. The extracellularmatrix may be diluted prior to coating the tissue culture substrate.Examples of suitable methods for diluting the extracellular matrix andfor coating the tissue culture substrate may be found in Kleinman, H.K., et al., Biochemistry 25:312 (1986), and Hadley, M. A., et al., J.Cell. Biol. 101:1511 (1985).

Formation of the pancreas arises from the differentiation of definitiveendoderm into pancreatic endoderm. Cells of the pancreatic endodermexpress the pancreatic-duodenal homeobox gene, Pdx1. In the absence ofPdx1, the pancreas fails to develop beyond the formation of ventral anddorsal buds. Thus, Pdx1 expression marks a critical step in pancreaticorganogenesis. The mature pancreas contains, among other cell types,exocrine tissue and endocrine tissue. Exocrine and endocrine tissuesarise from the differentiation of pancreatic endoderm.

Cells bearing the features of islet cells have reportedly been derivedfrom embryonic cells of the mouse. For example, Lumelsky et al. (Science292:1389, 2001) report differentiation of mouse embryonic stem cells toinsulin-secreting structures similar to pancreatic islets. Soria et al.(Diabetes 49:157, 2000) report that insulin-secreting cells derived frommouse embryonic stem cells normalize glycemia in streptozotocin-induceddiabetic mice.

In one example, Hon et al. (PNAS 99: 16105, 2002) disclose thattreatment of mouse embryonic stem cells with inhibitors ofphosphoinositide 3-kinase (LY294002) produced cells that resembled βcells.

In another example, Blyszczuk et al. (PNAS 100:998, 2003) reports thegeneration of insulin-producing cells from mouse embryonic stem cellsconstitutively expressing Pax4.

Micallef et al. reports that retinoic acid can regulate the commitmentof embryonic stem cells to form Pdx1 positive pancreatic endoderm.Retinoic acid is most effective at inducing Pdx1 expression when addedto cultures at day 4 of embryonic stem cell differentiation during aperiod corresponding to the end of gastrulation in the embryo (Diabetes54:301, 2005).

Miyazaki et al. reports a mouse embryonic stem cell line over-expressingPdx1. Their results show that exogenous Pdx1 expression clearly enhancedthe expression of insulin, somatostatin, glucokinase, neurogenin3, P48,Pax6, and HNF6 genes in the resulting differentiated cells (Diabetes 53:1030, 2004).

Skoudy et al. reports that activin A (a member of the TGF-β superfamily)upregulates the expression of exocrine pancreatic genes (p48 andamylase) and endocrine genes (Pdx1, insulin, and glucagon) in mouseembryonic stem cells. The maximal effect was observed using 1 nM activinA. They also observed that the expression level of insulin and Pdx1 mRNAwas not affected by retinoic acid; however, 3 nM FGF7 treatment resultedin an increased level of the transcript for Pdx1 (Biochem. J. 379: 749,2004).

Shiraki et al. studied the effects of growth factors that specificallyenhance differentiation of embryonic stem cells into Pdx1 positivecells. They observed that TGF-β2 reproducibly yielded a higherproportion of Pdx1 positive cells (Genes Cells. 2005 June; 10(6):503-16.).

Gordon et al. demonstrated the induction of brachyury⁺/HNF-3beta⁺endoderm cells from mouse embryonic stem cells in the absence of serumand in the presence of activin along with an inhibitor of Wnt signaling(US 2006/0003446A1).

Gordon et al. (PNAS, Vol 103, page 16806, 2006) states “Wnt andTGF-beta/nodal/activin signaling simultaneously were required for thegeneration of the anterior primitive streak”.

However, the mouse model of embryonic stem cell development may notexactly mimic the developmental program in higher mammals, such as, forexample, humans.

Thomson et al. isolated embryonic stem cells from human blastocysts(Science 282:114, 1998). Concurrently, Gearhart and coworkers derivedhuman embryonic germ (hEG) cell lines from fetal gonadal tissue(Shamblott et al., Proc. Natl. Acad. Sci. USA 95:13726, 1998). Unlikemouse embryonic stem cells, which can be prevented from differentiatingsimply by culturing with Leukemia Inhibitory Factor (LIF), humanembryonic stem cells must be maintained under very special conditions(U.S. Pat. No. 6,200,806; WO 99/20741; WO 01/51616).

D'Amour et al. describes the production of enriched cultures of humanembryonic stem cell-derived definitive endoderm in the presence of ahigh concentration of activin and low serum (Nature Biotechnology 2005).Transplanting these cells under the kidney capsule of mice resulted indifferentiation into more mature cells with characteristic of someendodermal organs. Human embryonic stem cell-derived definitive endodermcells can be further differentiated into Pdx1 positive cells afteraddition of FGF-10 (US 2005/0266554A1).

D'Amour et al. (Nature Biotechnology, 24, 1392-1401 (2006)) states: “Wehave developed a differentiation process that converts human embryonicstem (hES) cells to endocrine cells capable of synthesizing thepancreatic hormones insulin, glucagon, somatostatin, pancreaticpolypeptide and ghrelin. This process mimics in vivo pancreaticorganogenesis by directing cells through stages resembling definitiveendoderm, gut-tube endoderm, pancreatic endoderm and endocrine precursoren route to cells that express endocrine hormones”.

In another example, Fisk et al. reports a system for producingpancreatic islet cells from human embryonic stem cells(US2006/0040387A1). In this case, the differentiation pathway wasdivided into three stages. Human embryonic stem cells were firstdifferentiated to endoderm using a combination of sodium butyrate andactivin A. The cells were then cultured with TGF-β antagonists such asNoggin in combination with EGF or betacellulin to generate Pdx1 positivecells. The terminal differentiation was induced by nicotinamide.

In one example, Benvenistry et al. states: “We conclude thatover-expression of Pdx1 enhanced expression of pancreatic enrichedgenes, induction of insulin expression may require additional signalsthat are only present in vivo” (Benvenistry et al., Stem Cells 2006;24:1923-1930).

In another example, Odorico et al. reports methods for direct in vitrodifferentiation of mammalian pluripotent stem cells to cells of thepancreatic lineage. The methods involve culturing the stem cells in thepresence of an effective amount of a bone morphogenetic protein toinduce differentiation in the direction of mesendoderm. Thesemesendoderm cells are further cultured to form embryoid bodies (EBs)enriched for definitive endoderm committed cells, which under definedconditions terminally differentiate to cells of the pancreatic lineage(US20070259423).

In another example, Tulachan et al. (Developmental Biology, 305, 2007,Pgs 508-521) state: “Inhibition of TGF-B signaling in the embryonicperiod may thus allow pancreatic epithelial cells to progress towardsthe endocrine lineage”.

Therefore, there still remains a significant need to develop conditionsfor establishing pluripotent stem cell lines that can be expanded toaddress the current clinical needs, while retaining the potential todifferentiate into pancreatic endocrine cells, pancreatic hormoneexpressing cells, or pancreatic hormone secreting cells, and possess theability to secrete insulin in response to changes in glucoseconcentration. An alternative approach has been taken to improve theefficiency of differentiating human embryonic stem cells towardpancreatic endocrine cells that are able to secrete insulin in responseto changes in glucose levels.

SUMMARY

In one embodiment, the present invention provides a method for producingcells capable of glucose-stimulated insulin secretion from pluripotentstem cells, comprising the steps of: Culturing the pluripotent stemcells,

-   -   b. Differentiating the pluripotent stem cells into cells        expressing markers characteristic of the definitive endoderm        lineage,    -   c. Differentiating the cells expressing markers characteristic        of the definitive endoderm lineage into cells expressing markers        characteristic of the pancreatic endoderm lineage, and    -   d. Differentiating the cells expressing markers characteristic        of the pancreatic endoderm lineage into cells expressing markers        characteristic of the pancreatic endocrine lineage.

In one embodiment, the present invention provides a method for promotingglucose-stimulated insulin secretion in cells expressing markerscharacteristic of the pancreatic endocrine lineage derived frompluripotent stem cells, comprising the steps of:

-   -   a. Culturing the pluripotent stem cells,    -   b. Differentiating the pluripotent stem cells into cells        expressing markers characteristic of the definitive endoderm        lineage,    -   c. Differentiating the cells expressing markers characteristic        of the definitive endoderm lineage into cells expressing markers        characteristic of the pancreatic endoderm lineage, and    -   d. Differentiating the cells expressing markers characteristic        of the pancreatic endoderm lineage into cells expressing markers        characteristic of the pancreatic endocrine lineage.

In one embodiment, cells expressing markers characteristic of thepancreatic endoderm lineage are differentiated from cells expressingmarkers characteristic of the definitive endoderm lineage by treatingcells expressing markers characteristic of the definitive endodermlineage by any one of the following methods:

-   -   a. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with a fibroblast growth factor and        a hedgehog signaling pathway inhibitor, then removing the medium        containing the fibroblast growth factor and the hedgehog        signaling pathway inhibitor and subsequently culturing the cells        in medium containing retinoic acid, a fibroblast growth factor        and the hedgehog signaling pathway inhibitor, or    -   b. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with retinoic acid and at least one        fibroblast growth factor, or    -   c. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with retinoic acid, a sonic hedgehog        inhibitor, at least one fibroblast growth factor, and at least        one factor capable of inhibiting BMP, or    -   d. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with retinoic acid, a sonic hedgehog        inhibitor, at least one fibroblast growth factor, and a netrin,        or    -   e. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with retinoic acid, a sonic hedgehog        inhibitor, at least one fibroblast growth factor, at least one        factor capable of inhibiting BMP, and a netrin, or    -   f. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with at least one fibroblast growth        factor and a sonic hedgehog inhibitor, then removing the at        least one fibroblast growth factor and the sonic hedgehog        inhibitor and subsequently treating the cells with a sonic        hedgehog inhibitor, at least one fibroblast growth factor, and        retinoic acid, or    -   g. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with at least one fibroblast growth        factor and a sonic hedgehog inhibitor, then removing the at        least one fibroblast growth factor and the sonic hedgehog        inhibitor and subsequently treating the cells with a sonic        hedgehog inhibitor, at least one fibroblast growth factor,        retinoic acid, and at least one factor capable of inhibiting        BMP, or    -   h. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with at least one fibroblast growth        factor and a sonic hedgehog inhibitor, then removing the at        least one fibroblast growth factor and the sonic hedgehog        inhibitor and subsequently treating the cells with a sonic        hedgehog inhibitor, at least one fibroblast growth factor,        retinoic acid, and a netrin, or    -   i. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with at least one fibroblast growth        factor and a sonic hedgehog inhibitor, then removing the at        least one fibroblast growth factor and the sonic hedgehog        inhibitor and subsequently treating the cells with a sonic        hedgehog inhibitor, at least one fibroblast growth factor,        retinoic acid, at least one factor capable of inhibiting BMP,        and a netrin.

In one embodiment, cells expressing markers characteristic of thepancreatic endocrine lineage are differentiated from cells expressingmarkers characteristic of the pancreatic endoderm lineage by treatingcells expressing markers characteristic of the pancreatic endodermlineage by any one of the following methods:

-   -   a. Culturing the cells expressing markers characteristic of the        pancreatic endoderm lineage in medium containing a γ secretase        inhibitor and a GLP-1 agonist, then removing the medium        containing a γ secretase inhibitor and a GLP-1 agonist and        subsequently culturing the cells in medium containing a GLP-1        agonist, IGF-1 and HGF, or    -   b. Culturing the cells expressing markers characteristic of the        pancreatic endoderm lineage in medium containing a GLP-1        agonist, then removing the medium containing a GLP-1 agonist and        subsequently culturing the cells in medium containing a GLP-1        agonist, IGF-1 and HGF, or    -   c. Culturing the cells expressing markers characteristic of the        pancreatic endoderm lineage in medium containing a γ secretase        inhibitor and a GLP-1 agonist, or    -   d. Culturing the cells expressing markers characteristic of the        pancreatic endoderm lineage in medium containing a GLP-1        agonist, or    -   e. Treating the cells expressing markers characteristic of the        pancreatic endoderm lineage with a factor that inhibits the        Notch signaling pathway, or    -   f. Treating the cells expressing markers characteristic of the        pancreatic endoderm lineage with a factor that inhibits the        TGF-βR-1 pathway, or    -   g. Treating the cells expressing markers characteristic of the        pancreatic endoderm lineage with a factor that inhibits the        Notch signaling pathway, and a factor that inhibits the TGF-βR-1        pathway, or    -   h. Culturing the cells expressing markers characteristic of the        pancreatic endoderm lineage in medium containing from about 10        mM to about 20 mM glucose and a GLP-1 agonist.

BRIEF DESCRIPTION OF THE DRAWINGS

FIGS. 1A-1C show an outline of the differentiation protocol used in thepresent invention. FIG. 1A) refers to the method reported in U.S. patentapplication Ser. No. 11/736,908, and FIG. 1B) and FIG. 1C) are themethods of the present invention.

FIG. 2 shows real-time PCR analysis of cells of the human embryonic stemcell line H1, differentiated according to the methods disclosed inExample 2. Expression of pancreatic endoderm (PDX-1, ISL-1) andendocrine markers (NeuroD, Insulin, and glucagon) is depicted at stages3 to 5 (S3-S5). There was a significant increase in expression ofinsulin and glucagon at stages 4 to 5.

FIGS. 3A-3E show real-time PCR analysis of cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 3. Pancreatic endocrine FIG. 3A) insulin, FIG. 3B) NKX2, FIG.3C) glucagon, FIG. 3D) NeuroD, and pancreatic endoderm marker FIG. 3E)PDX-1 at stages 3 to 5. The effect of various kinase inhibitors wereevaluated at either stage 3, stage 4, or at stages 3 and 4. (+/+ refersto the presence of a particular compound at both stages 3 and 4, +/−refers to the presence of a particular compound at stage 3 and itsabsence at stage 4, −/+ refers to the presence of a particular compoundat stage 4 and its absence at stage 3).

FIGS. 4A-4D show real-time PCR analysis of cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 4. Pancreatic markers FIG. 4A) glucagon and insulin, FIG. 4B)HAND1 and NeuroD, FIG. 4C) HNF4a and PDX-1, FIG. 4D) NKX2.2 and Sox17,is depicted at stages 3 to 5. The effect of ALK5 inhibitor II wasvaluated at either stage 4, stage 5, or at stages 4 and 5. (+/+ refersto the presence of the inhibitor at both stages 4+5, +/− refers to thepresence of the inhibitor at stage 4 and its absence at stage 5, −/+refers to the presence of the inhibitor at stage Sand its absence atstage 4).

FIGS. 5A-5D show real-time PCR analysis of cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 5. Effect of 1-10 μm ALK5 inhibitors I and II, on the expressionof: FIG. 5A) glucagon, FIG. 5B) insulin, FIG. 5C) PDX-1, FIG. 5D)NeuroD, is depicted at stages 4 to 5. Control treatment did not includeany ALK5 inhibitor during the differentiation process.

FIGS. 6A-6G show real-time PCR analysis of cells of the human embryonicstem cell line H1, differentiated according to the methods disclosedExample 6. Combined effects of 1 μM ALK5 inhibitor and 0-500 ng/ml ofrecombinant human Noggin on expression of FIG. 6A) albumin, FIG. 6B)CDX2, FIG. 6C) insulin, FIG. 6D) glucagon, FIG. 6E) PDX-1, FIG. 6F)NeuroD, and FIG. 6G) NKX2.2, is depicted at stages 3 to 5. ALK5inhibitor was added at stages 4 and 5 and Noggin was added at stage 3.

FIGS. 7A-7F show real-time PCR analysis of cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 7. Combined effects of 1 μM ALK5 inhibitor and 100 ng/ml ofrecombinant human Noggin on expression of FIG. 7A) insulin, FIG. 7B)glucagon, FIG. 7C) ngn3, FIG. 7D) NeuroD, FIG. 7E) CDX-2, FIG. 7F)PDX-1, is depicted at stages 4 and 5. ALK5 inhibitor was added at stages4 and 5 and Noggin was added at stage 3, 4, or 3 and 4.

FIGS. 8A-8D show the morphology of cells differentiated according themethods disclosed in Example 7. FIG. 8A) 4× phase contrast image ofstage 5 cells at day 6, FIG. 8B) 10× phase contrast image of stage 5cells at day 6, FIG. 8C) 4× phase contrast image of stage 5 cells at day12, FIG. 8D) 10× phase contrast image of stage 5 cells at day 12.

FIGS. 9A-9B show the immunofluorescent images of cells, differentiatedaccording to the methods disclosed in Example 7. Cells are at stage 5 atday 12. FIG. 9A) Insulin staining of a single cluster along with FIG.9B) DAPI nuclear stain.

FIG. 10 shows real-time PCR analysis cells of the human embryonic stemcell line H1, differentiated according to the methods disclosed inExample 7.

FIGS. 11A-11F show real-time PCR analysis cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 8. The data depicts the combined effects of Noggin added atstages 3 and 4, together with Netrin-4 and/or ALK 5 inhibitor added atstage 4 on the expression of FIG. 11A) ngn3, FIG. 11B) PDX-1, FIG. 11C)NeuroD, FIG. 11D) Pax4, FIG. 11E) insulin, and FIG. 11F) glucagon.

FIGS. 12A-12F show real-time PCR analysis cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 8. FIG. 12A) insulin, FIG. 12B) glucagon, FIG. 12C) ngn3, FIG.12D) NKX2.2, FIG. 12E) NeuroD, and FIG. 12F) PDX-1.

FIGS. 13A-13C show the in vitro Glucose Stimulated Insulin Secretion(GSIS) of extended stage 5 cultures. Stage 5 cells prepared according tothe methods disclosed in Example 9 were glucose challenged at days FIG.13A) 6, FIG. 13B) 12, and FIG. 13C) 8-20 days in culture at stage 5.

FIG. 14 shows the effect of Netrin-1 or Netrin-2 on expression ofendocrine markers. Real-time PCR analysis cells of the human embryonicstem cell line H1, differentiated according to the methods disclosed inExample 10.

FIGS. 15A-15F show the induction of endocrine markers using analternative method to induce definitive endoderm. Real-time PCR analysiscells of the human embryonic stem cell line H1, differentiated accordingto the methods disclosed in Example 11. FIG. 15A) insulin, FIG. 15B)glucagon, FIG. 15C) NKX2.2, FIG. 15D) Pax4, FIG. 15E) PDX-1, and FIG.15F) NeuroD.

FIGS. 16A-16N show the expression of various markers at the variousstages of the differentiation protocol outlined in FIG. 1C. FIG. 16A):shows the expression of CXCR4, as determined by FACS in H1 cells at daythree of stage 1. FIG. 16B) shows the expression of markerscharacteristic of the definitive endoderm lineage and theextra-embryonic lineage, in cells at day three of stage 1, as determinedby real-time PCR. FIGS. 16C-16N) show the expression of various genes incells harvested at the end of stages 2-6, as determined by real-timePCR.

FIG. 17 shows the number of cells at the various stages of thedifferentiation protocol outlined in FIG. 1C.

FIG. 18 shows C-peptide release from cells at the end of stage 6 of thedifferentiation protocol outlined in FIG. 1C in response to variousstimuli.

FIG. 19 shows C-peptide and pro-insulin content in cells at the end ofstage 6 of the differentiation protocol outlined in FIG. 1C compared toadult human pancreatic islets.

FIGS. 20A-20C show the expression of insulin (FIG. 20A), synaptophysin(FIG. 20B) and co-expression of synaptophysin (X-axis) and insulin(Y-axis) (FIG. 20C) in cells at the end of stage 6 of thedifferentiation protocol outlined in FIG. 1C.

FIGS. 21A-21D show the expression of synaptophysin (FIG. 21A and FIG.21C) and insulin (FIG. 21B and FIG. 21D) in cells at the end of stage 6of the differentiation protocol outlined in FIG. 1C, that were treatedwith 100 ng/ml of Chordin instead of Noggin at stages 3-4.

FIGS. 22A-22L show the expression of various markers in cells of thehuman embryonic stem cell line H9 treated according to thedifferentiation protocol outlined in FIG. 1C. Data shown is theexpression of FIG. 22A) HNF4a, FIG. 22B) HNF6, FIG. 22C) CDX2, FIG. 22D)PDX-1, FIG. 22E) NKX6.1, FIG. 22F) Pax4, FIG. 22G) NKX2.2, FIG. 22H)NeuroD, FIG. 22I) NGN3, FIG. 22J) PECAM FIG. 22K) glucagon, and FIG.22L) insulin, as determined by real-time PCR in cells harvested at theend of stages 3-6.

FIGS. 23A-23D shows the expression of various markers in cells of thehuman embryonic stem cell line H1 treated according to thedifferentiation protocol outlined in FIG. 1C, where the cells weretreated with either B27 or N2. Data shown is the expression of FIG. 23A)CDX2, FIG. 23B) glucagon, FIG. 23C) insulin, and FIG. 23D) PDX-1, asdetermined by real-time PCR in cells harvested at the end of stages 3-6.

DETAILED DESCRIPTION

For clarity of disclosure, and not by way of limitation, the detaileddescription of the invention is divided into the following subsectionsthat describe or illustrate certain features, embodiments orapplications of the present invention.

Definitions

Stem cells are undifferentiated cells defined by their ability at thesingle cell level to both self-renew and differentiate to produceprogeny cells, including self-renewing progenitors, non-renewingprogenitors, and terminally differentiated cells. Stem cells are alsocharacterized by their ability to differentiate in vitro into functionalcells of various cell lineages from multiple germ layers (endoderm,mesoderm and ectoderm), as well as to give rise to tissues of multiplegerm layers following transplantation and to contribute substantially tomost, if not all, tissues following injection into blastocysts.

Stem cells are classified by their developmental potential as: (1)totipotent, meaning able to give rise to all embryonic andextraembryonic cell types; (2) pluripotent, meaning able to give rise toall embryonic cell types; (3) multipotent, meaning able to give rise toa subset of cell lineages but all within a particular tissue, organ, orphysiological system (for example, hematopoietic stem cells (HSC) canproduce progeny that include HSC (self-renewal), blood cell restrictedoligopotent progenitors, and all cell types and elements (e.g.,platelets) that are normal components of the blood); (4) oligopotent,meaning able to give rise to a more restricted subset of cell lineagesthan multipotent stem cells; and (5) unipotent, meaning able to giverise to a single cell lineage (e.g., spermatogenic stem cells).

Differentiation is the process by which an unspecialized (“uncommitted”)or less specialized cell acquires the features of a specialized cellsuch as, for example, a nerve cell or a muscle cell. A differentiated ordifferentiation-induced cell is one that has taken on a more specialized(“committed”) position within the lineage of a cell. The term“committed”, when applied to the process of differentiation, refers to acell that has proceeded in the differentiation pathway to a point where,under normal circumstances, it will continue to differentiate into aspecific cell type or subset of cell types, and cannot, under normalcircumstances, differentiate into a different cell type or revert to aless differentiated cell type. De-differentiation refers to the processby which a cell reverts to a less specialized (or committed) positionwithin the lineage of a cell. As used herein, the lineage of a celldefines the heredity of the cell, i.e., which cells it came from andwhat cells it can give rise to. The lineage of a cell places the cellwithin a hereditary scheme of development and differentiation. Alineage-specific marker refers to a characteristic specificallyassociated with the phenotype of cells of a lineage of interest and canbe used to assess the differentiation of an uncommitted cell to thelineage of interest.

“β-cell lineage” refers to cells with positive gene expression for thetranscription factor PDX-1 and at least one of the followingtranscription factors: NGN-3, Nkx2.2, Nkx6.1, NeuroD, Isl-1, HNF-3 beta,MAFA, Pax4, and Pax6. Cells expressing markers characteristic of the 13cell lineage include β cells.

“Cells expressing markers characteristic of the definitive endodermlineage”, as used herein, refers to cells expressing at least one of thefollowing markers: SOX-17, GATA-4, HNF-3 beta, GSC, Cer1, Nodal, FGF8,Brachyury, Mix-like homeobox protein, FGF4 CD48, eomesodermin (EOMES),DKK4, FGF17, GATA-6, CXCR4, C-Kit, CD99, or OTX2. Cells expressingmarkers characteristic of the definitive endoderm lineage includeprimitive streak precursor cells, primitive streak cells, mesendodermcells and definitive endoderm cells.

“Cells expressing markers characteristic of the pancreatic endodermlineage”, as used herein, refers to cells expressing at least one of thefollowing markers: PDX-1, HNF-1beta, PTF-1 alpha, HNF-6, or HB9. Cellsexpressing markers characteristic of the pancreatic endoderm lineageinclude pancreatic endoderm cells, primitive gut tube cells, andposterior foregut cells.

“Cells expressing markers characteristic of the pancreatic endocrinelineage”, as used herein, refers to cells expressing at least one of thefollowing markers: NGN-3, NeuroD, Islet-1, PDX-1, NKX6.1, Pax-4, orPTF-1 alpha. Cells expressing markers characteristic of the pancreaticendocrine lineage include pancreatic endocrine cells, pancreatic hormoneexpressing cells, and pancreatic hormone secreting cells, and cells ofthe β-cell lineage.

“Definitive endoderm”, as used herein, refers to cells which bear thecharacteristic of cells arising from the epiblast during gastrulationand which form the gastrointestinal tract and its derivatives.Definitive endoderm cells express the following markers: HNF-3 beta,GATA-4, SOX-17, Cerberus, OTX2, goosecoid, C-Kit, CD99, and Mix11.

“Extraembryonic endoderm”, as used herein, refers to a population ofcells expressing at least one of the following markers: SOX-7, AFP, andSPARC.

“Markers”, as used herein, are nucleic acid or polypeptide moleculesthat are differentially expressed in a cell of interest. In thiscontext, differential expression means an increased level for a positivemarker and a decreased level for a negative marker. The detectable levelof the marker nucleic acid or polypeptide is sufficiently higher orlower in the cells of interest compared to other cells, such that thecell of interest can be identified and distinguished from other cellsusing any of a variety of methods known in the art.

“Mesendoderm cell”, as used herein, refers to a cell expressing at leastone of the following markers: CD48, eomesodermin (EOMES), SOX-17, DKK4,HNF-3 beta, GSC, FGF17, GATA-6.

“Pancreatic endocrine cell”, or “pancreatic hormone expressing cell”, asused herein, refers to a cell capable of expressing at least one of thefollowing hormones: insulin, glucagon, somatostatin, and pancreaticpolypeptide.

“Pancreatic endoderm cell”, as used herein, refers to a cell capable ofexpressing at least one of the following markers: NGN-3, NeuroD,Islet-1, PDX-1, PAX-4, NKX2.2.

“Pancreatic hormone producing cell”, as used herein, refers to a cellcapable of producing at least one of the following hormones: insulin,glucagon, somatostatin, and pancreatic polypeptide.

“Pancreatic hormone secreting cell” as used herein, refers to a cellcapable of secreting at least one of the following hormones: insulin,glucagon, somatostatin, and pancreatic polypeptide.

“Posterior foregut cell”, as used herein, refers to a cell capable ofsecreting at least one of the following markers: PDX-1, HNF-1, PTF-1A,HNF-6, HB-9, PROX-1.

“Pre-primitive streak cell”, as used herein, refers to a cell expressingat least one of the following markers: Nodal, or FGF8.

“Primitive gut tube cell”, as used herein, refers to a cell capable ofsecreting at least one of the following markers: HNF-1, HNF-4A.

“Primitive streak cell”, as used herein, refers to a cell expressing atleast one of the following markers: Brachyury, Mix-like homeoboxprotein, or FGF4.

Isolation, Expansion and Culture of Pluripotent Stem CellsCharacterization of Pluripotent Stem Cells

Pluripotent stem cells may express one or more of the stage-specificembryonic antigens (SSEA) 3 and 4, and markers detectable usingantibodies designated Tra-1-60 and Tra-1-81 (Thomson et al., Science282:1145, 1998). Differentiation of pluripotent stem cells in vitroresults in the loss of SSEA-4, Tra-1-60, and Tra-1-81 expression (ifpresent) and increased expression of SSEA-1. Undifferentiatedpluripotent stem cells typically have alkaline phosphatase activity,which can be detected by fixing the cells with 4% paraformaldehyde, andthen developing with Vector Red as a substrate, as described by themanufacturer (Vector Laboratories, Burlingame Calif.). Undifferentiatedpluripotent stem cells also typically express Oct-4 and TERT, asdetected by RT-PCR.

Another desirable phenotype of propagated pluripotent stem cells is apotential to differentiate into cells of all three germinal layers:endoderm, mesoderm, and ectoderm tissues. Pluripotency of pluripotentstem cells can be confirmed, for example, by injecting cells into severecombined immunodeficient (SCID) mice, fixing the teratomas that formusing 4% paraformaldehyde, and then examining them histologically forevidence of cell types from the three germ layers. Alternatively,pluripotency may be determined by the creation of embryoid bodies andassessing the embryoid bodies for the presence of markers associatedwith the three germinal layers.

Propagated pluripotent stem cell lines may be karyotyped using astandard G-banding technique and compared to published karyotypes of thecorresponding primate species. It is desirable to obtain cells that havea “normal karyotype,” which means that the cells are euploid, whereinall human chromosomes are present and not noticeably altered.

Sources of Pluripotent Stem Cells

The types of pluripotent stem cells that may be used include establishedlines of pluripotent cells derived from tissue formed after gestation,including pre-embryonic tissue (such as, for example, a blastocyst),embryonic tissue, or fetal tissue taken any time during gestation,typically but not necessarily before approximately 10-12 weeksgestation. Non-limiting examples are established lines of humanembryonic stem cells or human embryonic germ cells, such as, for examplethe human embryonic stem cell lines H1, H7, and H9 (WiCell). Alsocontemplated is use of the compositions of this disclosure during theinitial establishment or stabilization of such cells, in which case thesource cells would be primary pluripotent cells taken directly from thesource tissues. Also suitable are cells taken from a pluripotent stemcell population already cultured in the absence of feeder cells. Alsosuitable are mutant human embryonic stem cell lines, such as, forexample, BG01v (BresaGen, Athens, Ga.).

In one embodiment, human embryonic stem cells are prepared as describedby Thomson et al. (U.S. Pat. No. 5,843,780; Science 282:1145, 1998;Curr. Top. Dev. Biol. 38:133 ff., 1998; Proc. Natl. Acad. Sci. U.S.A.92:7844, 1995).

Culture of Pluripotent Stem Cells

In one embodiment, pluripotent stem cells are typically cultured on alayer of feeder cells that support the pluripotent stem cells in variousways. Alternatively, pluripotent stem cells are cultured in a culturesystem that is essentially free of feeder cells, but nonethelesssupports proliferation of pluripotent stem cells without undergoingsubstantial differentiation. The growth of pluripotent stem cells infeeder-free culture without differentiation is supported using a mediumconditioned by culturing previously with another cell type.Alternatively, the growth of pluripotent stem cells in feeder-freeculture without differentiation is supported using a chemically definedmedium.

The pluripotent stem cells may be plated onto a suitable culturesubstrate. In one embodiment, the suitable culture substrate is anextracellular matrix component, such as, for example, those derived frombasement membrane or that may form part of adhesion moleculereceptor-ligand couplings. In one embodiment, a suitable culturesubstrate is MATRIGEL® (Becton Dickenson). MATRIGEL® is a solublepreparation from Engelbreth-Holm-Swarm tumor cells that gels at roomtemperature to form a reconstituted basement membrane. Otherextracellular matrix components and component mixtures are suitable asan alternative. Depending on the cell type being proliferated, this mayinclude laminin, fibronectin, proteoglycan, entactin, heparan sulfate,and the like, alone or in various combinations.

The pluripotent stem cells may be plated onto the substrate in asuitable distribution and in the presence of a medium that promotes cellsurvival, propagation, and retention of the desirable characteristic.All these characteristic benefit from careful attention to the seedingdistribution and can readily be determined by one of skill in the art.

Suitable culture media may be made from the following components, suchas, for example, Dulbecco's modified Eagle's medium (DMEM), Gibco#11965-092; Knockout Dulbecco's modified Eagle's medium (KO DMEM), Gibco#10829-018; Ham's F12/50% DMEM basal medium; 200 mM L-glutamine, Gibco#15039-027; non-essential amino acid solution, Gibco 11140-050;β-mercaptoethanol, Sigma #M7522; human recombinant basic fibroblastgrowth factor (bFGF), Gibco #13256-029.

Formation of Cells Capable of Glucose-Stimulated Insulin Secretion fromPluripotent Stem Cells

In one embodiment, the present invention provides a method for producingcells capable of glucose-stimulated insulin secretion from pluripotentstem cells, comprising the steps of:

-   -   a. Culturing the pluripotent stem cells,    -   b. Differentiating the pluripotent stem cells into cells        expressing markers characteristic of the definitive endoderm        lineage,    -   c. Differentiating the cells expressing markers characteristic        of the definitive endoderm lineage into cells expressing markers        characteristic of the pancreatic endoderm lineage, and    -   d. Differentiating the cells expressing markers characteristic        of the pancreatic endoderm lineage into cells expressing markers        characteristic of the pancreatic endocrine lineage.

In one embodiment, the present invention provides a method for promotingglucose-stimulated insulin secretion in cells expressing markerscharacteristic of the pancreatic endocrine lineage derived frompluripotent stem cells, comprising the steps of:

-   -   a. Culturing the pluripotent stem cells,    -   b. Differentiating the pluripotent stem cells into cells        expressing markers characteristic of the definitive endoderm        lineage,    -   c. Differentiating the cells expressing markers characteristic        of the definitive endoderm lineage into cells expressing markers        characteristic of the pancreatic endoderm lineage, and    -   d. Differentiating the cells expressing markers characteristic        of the pancreatic endoderm lineage into cells expressing markers        characteristic of the pancreatic endocrine lineage.

Pluripotent stem cells suitable for use in the present inventioninclude, for example, the human embryonic stem cell line H9 (NIH code:WA09), the human embryonic stem cell line H1 (NIH code: WA01), the humanembryonic stem cell line H7 (NIH code: WA07), and the human embryonicstem cell line SA002 (Cellartis, Sweden). Also suitable for use in thepresent invention are cells that express at least one of the followingmarkers characteristic of pluripotent cells: ABCG2, cripto, CD9, FoxD3,Connexin43, Connexin45, Oct4, Sox2, Nanog, hTERT, UTF-1, ZFP42, SSEA-3,SSEA-4, Tra1-60, Tra1-81.

Markers characteristic of the definitive endoderm lineage are selectedfrom the group consisting of SOX-17, GATA4, Hnf-3beta, GSC, Cer1, Nodal,FGF8, Brachyury, Mix-like homeobox protein, FGF4 CD48, eomesodermin(EOMES), DKK4, FGF17, GATA6, CXCR4, C-Kit, CD99, and OTX2. Suitable foruse in the present invention is a cell that expresses at least one ofthe markers characteristic of the definitive endoderm lineage. In oneaspect of the present invention, a cell expressing markerscharacteristic of the definitive endoderm lineage is a primitive streakprecursor cell. In an alternate aspect, a cell expressing markerscharacteristic of the definitive endoderm lineage is a mesendoderm cell.In an alternate aspect, a cell expressing markers characteristic of thedefinitive endoderm lineage is a definitive endoderm cell.

Markers characteristic of the pancreatic endoderm lineage are selectedfrom the group consisting of Pdx1, HNF-1beta, PTF1a, HNF-6, HB9 andPROX1. Suitable for use in the present invention is a cell thatexpresses at least one of the markers characteristic of the pancreaticendoderm lineage. In one aspect of the present invention, a cellexpressing markers characteristic of the pancreatic endoderm lineage isa pancreatic endoderm cell.

Markers characteristic of the pancreatic endocrine lineage are selectedfrom the group consisting of NGN-3, NeuroD, Islet-1, Pdx-1, NKX6.1,Pax-4, and PTF-1 alpha. In one embodiment, a pancreatic endocrine cellis capable of expressing at least one of the following hormones:insulin, glucagon, somatostatin, and pancreatic polypeptide. Suitablefor use in the present invention is a cell that expresses at least oneof the markers characteristic of the pancreatic endocrine lineage. Inone aspect of the present invention, a cell expressing markerscharacteristic of the pancreatic endocrine lineage is a pancreaticendocrine cell. The pancreatic endocrine cell may be a pancreatichormone expressing cell. Alternatively, the pancreatic endocrine cellmay be a pancreatic hormone secreting cell.

In one aspect of the present invention, the pancreatic endocrine cell isa cell expressing markers characteristic of the β cell lineage. A cellexpressing markers characteristic of the β cell lineage expresses Pdx1and at least one of the following transcription factors: NGN-3, Nkx2.2,Nkx6.1, NeuroD, Isl-1, HNF-3 beta, MAFA, Pax4, and Pax6. In one aspectof the present invention, a cell expressing markers characteristic ofthe β cell lineage is a β cell.

Formation of Cells Expressing Markers Characteristic of the DefinitiveEndoderm Lineage

Pluripotent stem cells may be differentiated into cells expressingmarkers characteristic of the definitive endoderm lineage by any methodin the art or by any method proposed in this invention.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineageaccording to the methods disclosed in D'Amour et al., NatureBiotechnology 23, 1534-1541 (2005).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineageaccording to the methods disclosed in Shinozaki et al., Development 131,1651-1662 (2004).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineageaccording to the methods disclosed in McLean et al., Stem Cells 25,29-38 (2007).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineageaccording to the methods disclosed in D'Amour et al., NatureBiotechnology 24, 1392-1401 (2006).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage byculturing the pluripotent stem cells in medium containing activin A inthe absence of serum, then culturing the cells with activin A and serum,and then culturing the cells with activin A and serum of a differentconcentration. An example of this method is disclosed in D'Amour et al.,Nature Biotechnology 23, 1534-1541 (2005).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage byculturing the pluripotent stem cells in medium containing activin A inthe absence of serum, then culturing the cells with activin A with serumof another concentration. An example of this method is disclosed inD'Amour et al., Nature Biotechnology, 2005.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage byculturing the pluripotent stem cells in medium containing activin A anda Wnt ligand in the absence of serum, then removing the Wnt ligand andculturing the cells with activin A with serum. An example of this methodis disclosed in Nature Biotechnology 24, 1392-1401 (2006).

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 11/736,908, assigned to LifeScan,Inc.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 11/779,311, assigned to LifeScan,Inc.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 61/076,889.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 61/076,900.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 61/076,908.

For example, pluripotent stem cells may be differentiated into cellsexpressing markers characteristic of the definitive endoderm lineage bytreating the pluripotent stem cells according to the methods disclosedin U.S. patent application Ser. No. 61/076,915.

Detection of Cells Expressing Markers Characteristic of the DefinitiveEndoderm Lineage

Formation of cells expressing markers characteristic of the definitiveendoderm lineage may be determined by testing for the presence of themarkers before and after following a particular protocol. Pluripotentstem cells typically do not express such markers. Thus, differentiationof pluripotent cells is detected when cells begin to express them.

The efficiency of differentiation may be determined by exposing atreated cell population to an agent (such as an antibody) thatspecifically recognizes a protein marker expressed by cells expressingmarkers characteristic of the definitive endoderm lineage.

Methods for assessing expression of protein and nucleic acid markers incultured or isolated cells are standard in the art. These includequantitative reverse transcriptase polymerase chain reaction (RT-PCR),Northern blots, in situ hybridization (see, e.g., Current Protocols inMolecular Biology (Ausubel et al., eds. 2001 supplement)), andimmunoassays such as immunohistochemical analysis of sectioned material,Western blotting, and for markers that are accessible in intact cells,flow cytometry analysis (FACS) (see, e.g., Harlow and Lane, UsingAntibodies: A Laboratory Manual, New York: Cold Spring Harbor LaboratoryPress (1998)).

Characteristic of pluripotent stem cells are well known to those skilledin the art, and additional characteristic of pluripotent stem cellscontinue to be identified. Pluripotent stem cell markers include, forexample, the expression of one or more of the following: ABCG2, cripto,FoxD3, Connexin43, Connexin45, Oct4, Sox2, Nanog, hTERT, UTF-1, ZFP42,SSEA-3, SSEA-4, Tra1-60, Tra1-81.

After treating pluripotent stem cells with the methods of the presentinvention, the differentiated cells may be purified by exposing atreated cell population to an agent (such as an antibody) thatspecifically recognizes a protein marker, such as CXCR4, expressed bycells expressing markers characteristic of the definitive endodermlineage.

Formation of Cells Expressing Markers Characteristic of the PancreaticEndoderm Lineage

Cells expressing markers characteristic of the definitive endodermlineage may be differentiated into cells expressing markerscharacteristic of the pancreatic endoderm lineage by any method in theart or by any method proposed in this invention.

For example, cells expressing markers characteristic of the definitiveendoderm lineage may be differentiated into cells expressing markerscharacteristic of the pancreatic endoderm lineage according to themethods disclosed in D'Amour et al., Nature Biotechnology 24, 1392-1401(2006).

For example, cells expressing markers characteristic of the definitiveendoderm lineage are further differentiated into cells expressingmarkers characteristic of the pancreatic endoderm lineage, by treatingthe cells expressing markers characteristic of the definitive endodermlineage with a fibroblast growth factor and the hedgehog signalingpathway inhibitor KAAD-cyclopamine, then removing the medium containingthe fibroblast growth factor and KAAD-cyclopamine and subsequentlyculturing the cells in medium containing retinoic acid, a fibroblastgrowth factor and KAAD-cyclopamine. An example of this method isdisclosed in Nature Biotechnology 24, 1392-1401 (2006).

In one aspect of the present invention, cells expressing markerscharacteristic of the definitive endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endoderm lineage, by treating the cells expressing markerscharacteristic of the definitive endoderm lineage with retinoic acid andat least one fibroblast growth factor for a period of time, according tothe methods disclosed in U.S. patent application Ser. No. 11/736,908,assigned to LifeScan, Inc.

In one aspect of the present invention, cells expressing markerscharacteristic of the definitive endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endoderm lineage, by treating the cells expressing markerscharacteristic of the definitive endoderm lineage with retinoic acid andat least one fibroblast growth factor for a period of time, according tothe methods disclosed in U.S. patent application Ser. No. 11/779,311,assigned to LifeScan, Inc.

In one embodiment, the present invention provides a method fordifferentiating cells expressing markers characteristic of thedefinitive endoderm lineage into cells expressing markers characteristicof the pancreatic endoderm lineage, comprising the steps of:

-   -   a. Culturing cells expressing markers characteristic of the        definitive endoderm lineage, and    -   b. Treating the cells expressing markers characteristic of the        definitive endoderm lineage with at least one factor selected        from the group consisting of retinoic acid, FGF-2, FGF-4, FGF-7,        FGF-10, a sonic hedgehog inhibitor, a factor capable of        inhibiting BMP, and a netrin.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm are treated with at least one factor selected fromthe group consisting of retinoic acid, FGF-2, FGF-4, FGF-7, FGF-10, asonic hedgehog inhibitor, a factor capable of inhibiting BMP, and anetrin for about one to about six days. In one embodiment, the cellsexpressing markers characteristic of the definitive endoderm are treatedwith at least one factor selected from the group consisting of retinoicacid, FGF-2, FGF-4, FGF-7, FGF-10, a sonic hedgehog inhibitor, a factorcapable of inhibiting BMP, and a netrin for about six days.

Any cell expressing markers characteristic of the definitive endodermlineage is suitable for differentiating into a cell expressing markerscharacteristic of the pancreatic endoderm lineage using this method.

In an alternate embodiment, the present invention provides a method fordifferentiating cells expressing markers characteristic of thedefinitive endoderm lineage into cells expressing markers characteristicof the pancreatic endoderm lineage, comprising the steps of:

-   -   a. Culturing cells expressing markers characteristic of the        definitive endoderm lineage,    -   b. Treating the cells expressing markers characteristic of the        definitive endoderm lineage treating the cells with at least one        factor selected from the group consisting of retinoic acid, and        a fibroblast growth factor, and    -   c. Removing the at least one factor selected from the group        consisting of retinoic acid, and a fibroblast growth factor and        subsequently treating the cells with at least one factor        selected from the group consisting of a sonic hedgehog        inhibitor, retinoic acid, a fibroblast growth factor, a factor        capable of inhibiting BMP, and a netrin.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm are treated with at least one factor selected fromthe group consisting of retinoic acid, and a fibroblast growth factorfor about one to about three days. In one embodiment, the cellsexpressing markers characteristic of the definitive endoderm are treatedwith at least one factor selected from the group consisting of retinoicacid, and a fibroblast growth factor for about three days. In oneembodiment, the cells expressing markers characteristic of thedefinitive endoderm are treated with at least one factor selected fromthe group consisting of a sonic hedgehog inhibitor, retinoic acid, afibroblast growth factor, a factor capable of inhibiting BMP, and anetrin for about one to about four days. In one embodiment, the cellsexpressing markers characteristic of the definitive endoderm are treatedwith at least one factor selected from the group consisting of a sonichedgehog inhibitor, retinoic acid, a fibroblast growth factor, a factorcapable of inhibiting BMP, and a netrin for about four days.

Any cell expressing markers characteristic of the definitive endodermlineage is suitable for differentiating into a cell expressing markerscharacteristic of the pancreatic endoderm lineage using this method.

In one embodiment, cells expressing markers characteristic of thepancreatic endoderm lineage produced by the methods of the presentinvention show a decreased level of expression of markers associatedwith liver and intestinal tissues. In one embodiment, cells expressingmarkers characteristic of the pancreatic endoderm lineage produced bythe methods of the present invention show a decreased level ofexpression of albumin and CDX-2.

The at least one fibroblast growth factor is selected from the groupconsisting of FGF-2, FGF-4, FGF-7 and FGF-10.

In one embodiment, the BMP is BMP4. In one embodiment, the at least onefactor capable of inhibiting BMP4 is noggin.

The netrin is selected from the group consisting of netrin 1, netrin 2,and netrin 4.

Retinoic acid may be used at a concentration from about 1 nM to about 1mM. In one embodiment, retinoic acid is used at a concentration of 1 μM.

FGF-2 may be used at a concentration from about 50 pg/ml to about 50μg/ml. In one embodiment, FGF-2 is used at a concentration of 50 ng/ml.

FGF-4 may be used at a concentration from about 50 pg/ml to about 50μg/ml. In one embodiment, FGF-4 is used at a concentration of 50 ng/ml.

FGF-7 may be used at a concentration from about 50 pg/ml to about 50μg/ml. In one embodiment, FGF-7 is used at a concentration of 50 ng/ml.

FGF-10 may be used at a concentration from about 50 pg/ml to about 50μg/ml. In one embodiment, FGF-10 is used at a concentration of 50 ng/ml.

Noggin may be used at a concentration from about 500 ng/ml to about 500μg/ml. In one embodiment, noggin is used at a concentration of 100ng/ml.

Netrin 1 may be used at a concentration from about 500 ng/ml to about500 μg/ml. In one embodiment, netrin 1 is used at a concentration of 100ng/ml.

Netrin 2 may be used at a concentration from about 500 ng/ml to about500 μg/ml. In one embodiment, netrin 2 is used at a concentration of 100ng/ml.

Netrin 4 may be used at a concentration from about 500 ng/ml to about500 μg/ml. In one embodiment, netrin 4 is used at a concentration of 100ng/ml.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with at least one of thefollowing factors: retinoic acid, FGF-2, FGF-4, FGF-7, FGF-10,cyclopamine, noggin, netrin 1, netrin 2, or netrin 4.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with retinoic acid, FGF-2,cyclopamine, and noggin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-4, cyclopamine, and noggin. In analternate embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with retinoic acid, FGF-7,cyclopamine, and noggin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-10, cyclopamine, and noggin.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with retinoic acid, FGF-2,cyclopamine, and a netrin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-4, cyclopamine, and a netrin. In analternate embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with retinoic acid, FGF-7,cyclopamine, and a netrin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-10, cyclopamine, and a netrin.

The netrin is selected from the group consisting of netrin 1, netrin 2,and netrin 4.

In one embodiment, the cells expressing markers characteristic of thedefinitive endoderm lineage are treated with retinoic acid, FGF-2,cyclopamine, noggin and a netrin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-4, cyclopamine, noggin and a netrin. Inan alternate embodiment, the cells expressing markers characteristic ofthe definitive endoderm lineage are treated with retinoic acid, FGF-7,cyclopamine, noggin and a netrin. In an alternate embodiment, the cellsexpressing markers characteristic of the definitive endoderm lineage aretreated with retinoic acid, FGF-10, cyclopamine, noggin and a netrin.

The netrin is selected from the group consisting of netrin 1, netrin 2,and netrin 4.

Cells expressing markers characteristic of the definitive endodermlineage may be treated with at least one other additional factor thatmay enhance the formation of cells expressing markers characteristic ofthe pancreatic endoderm lineage. Alternatively, the at least one otheradditional factor may enhance the proliferation of the cells expressingmarkers characteristic of the pancreatic endoderm lineage formed by themethods of the present invention. Further, the at least one otheradditional factor may enhance the ability of the cells expressingmarkers characteristic of the pancreatic endoderm lineage formed by themethods of the present invention to form other cell types, or improvethe efficiency of any other additional differentiation steps.

The at least one additional factor may be, for example, nicotinamide,members of TGF-β family, including TGF-β1, 2, and 3, serum albumin,members of the fibroblast growth factor family, platelet-derived growthfactor-AA, and -BB, platelet rich plasma, insulin growth factor (IGF-I,II), growth differentiation factor (GDF-5, -6, -8, -10, 11), glucagonlike peptide-I and II (GLP-I and II), GLP-1 and GLP-2 mimetobody,Exendin-4, retinoic acid, parathyroid hormone, insulin, progesterone,aprotinin, hydrocortisone, ethanolamine, beta mercaptoethanol, epidermalgrowth factor (EGF), gastrin I and II, copper chelators such as, forexample, triethylene pentamine, forskolin, Na-Butyrate, activin,betacellulin, ITS, noggin, neurite growth factor, nodal, valporic acid,trichostatin A, sodium butyrate, hepatocyte growth factor (HGF),sphingosine-1, VEGF, MG132 (EMD, CA), N2 and B27 supplements (Gibco,CA), steroid alkaloids such as, for example, cyclopamine (EMD, CA),keratinocyte growth factor (KGF), Dickkopf protein family, bovinepituitary extract, islet neogenesis-associated protein (INGAP), Indianhedgehog, sonic hedgehog, proteasome inhibitors, notch pathwayinhibitors, sonic hedgehog inhibitors, or combinations thereof.

The at least one other additional factor may be supplied by conditionedmedia obtained from pancreatic cells lines such as, for example, PANC-1(ATCC No: CRL-1469), CAPAN-1 (ATCC No: HTB-79), BxPC-3 (ATCC No:CRL-1687), HPAF-II (ATCC No: CRL-1997), hepatic cell lines such as, forexample, HepG2 (ATCC No: HTB-8065), and intestinal cell lines such as,for example, FHs 74 (ATCC No: CCL-241).

Detection of Cells Expressing Markers Characteristic of the PancreaticEndoderm Lineage

Markers characteristic of the pancreatic endoderm lineage are well knownto those skilled in the art, and additional markers characteristic ofthe pancreatic endoderm lineage continue to be identified. These markerscan be used to confirm that the cells treated in accordance with thepresent invention have differentiated to acquire the propertiescharacteristic of the pancreatic endoderm lineage. Pancreatic endodermlineage specific markers include the expression of one or moretranscription factors such as, for example, H1xb9, PTF-1a, PDX-1, HNF-6,HNF-1beta.

The efficiency of differentiation may be determined by exposing atreated cell population to an agent (such as an antibody) thatspecifically recognizes a protein marker expressed by cells expressingmarkers characteristic of the pancreatic endoderm lineage.

Methods for assessing expression of protein and nucleic acid markers incultured or isolated cells are standard in the art. These includequantitative reverse transcriptase polymerase chain reaction (RT-PCR),Northern blots, in situ hybridization (see, e.g., Current Protocols inMolecular Biology (Ausubel et al., eds. 2001 supplement)), andimmunoassays such as immunohistochemical analysis of sectioned material,Western blotting, and for markers that are accessible in intact cells,flow cytometry analysis (FACS) (see, e.g., Harlow and Lane, UsingAntibodies: A Laboratory Manual, New York: Cold Spring Harbor LaboratoryPress (1998)).

Formation of Cells Expressing Markers Characteristic of the PancreaticEndocrine Lineage

Cells expressing markers characteristic of the pancreatic endodermlineage may be differentiated into cells expressing markerscharacteristic of the pancreatic endocrine lineage by any method in theart or by any method disclosed in this invention.

For example, cells expressing markers characteristic of the pancreaticendoderm lineage may be differentiated into cells expressing markerscharacteristic of the pancreatic endocrine lineage according to themethods disclosed in D'Amour et al., Nature Biotechnology 24, 1392-1401(2006).

For example, cells expressing markers characteristic of the pancreaticendoderm lineage are further differentiated into cells expressingmarkers characteristic of the pancreatic endocrine lineage, by culturingthe cells expressing markers characteristic of the pancreatic endodermlineage in medium containing DAPT and exendin 4, then removing themedium containing DAPT and exendin 4 and subsequently culturing thecells in medium containing exendin 1, IGF-1 and HGF. An example of thismethod is disclosed in Nature Biotechnology 24, 1392-1401 (2006).

For example, cells expressing markers characteristic of the pancreaticendoderm lineage are further differentiated into cells expressingmarkers characteristic of the pancreatic endocrine lineage, by culturingthe cells expressing markers characteristic of the pancreatic endodermlineage in medium containing exendin 4, then removing the mediumcontaining exendin 4 and subsequently culturing the cells in mediumcontaining exendin 1, IGF-1 and HGF. An example of this method isdisclosed in D'Amour et al., Nature Biotechnology, 2006.

For example, cells expressing markers characteristic of the pancreaticendoderm lineage are further differentiated into cells expressingmarkers characteristic of the pancreatic endocrine lineage, by culturingthe cells expressing markers characteristic of the pancreatic endodermlineage in medium containing DAPT and exendin 4. An example of thismethod is disclosed in D'Amour et al., Nature Biotechnology, 2006.

For example, cells expressing markers characteristic of the pancreaticendoderm lineage are further differentiated into cells expressingmarkers characteristic of the pancreatic endocrine lineage, by culturingthe cells expressing markers characteristic of the pancreatic endodermlineage in medium containing exendin 4. An example of this method isdisclosed in D'Amour et al., Nature Biotechnology, 2006.

In one aspect of the present invention, cells expressing markerscharacteristic of the pancreatic endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endocrine lineage, by treating the cells expressing markerscharacteristic of the pancreatic endoderm lineage with a factor thatinhibits the Notch signaling pathway, according to the methods disclosedin U.S. patent application Ser. No. 11/736,908, assigned to LifeScan,Inc.

In one aspect of the present invention, cells expressing markerscharacteristic of the pancreatic endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endocrine lineage, by treating the cells expressing markerscharacteristic of the pancreatic endoderm lineage with a factor thatinhibits the Notch signaling pathway, according to the methods disclosedin U.S. patent application Ser. No. 11/779,311, assigned to LifeScan,Inc.

In one aspect of the present invention, cells expressing markerscharacteristic of the pancreatic endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endocrine lineage, by treating the cells expressing markerscharacteristic of the pancreatic endoderm lineage with a factor thatinhibits the Notch signaling pathway, according to the methods disclosedin U.S. patent application Ser. No. 60/953,178, assigned to LifeScan,Inc.

In one aspect of the present invention, cells expressing markerscharacteristic of the pancreatic endoderm lineage are furtherdifferentiated into cells expressing markers characteristic of thepancreatic endocrine lineage, by treating the cells expressing markerscharacteristic of the pancreatic endoderm lineage with a factor thatinhibits the TGF-βR-1 pathway. The factor that inhibits the TGF-βR-1pathway may be an antagonist for the TGF-β extracellular receptor-1.Alternatively, the factor may inhibit the biological activity of theTGF-βR-1 receptor. Alternatively, the factor may inhibit or be anantagonist of an element in the TGF-βR-1 signal transduction pathwaywithin a cell.

The cells expressing markers characteristic of the pancreatic endodermlineage are treated with the factor inhibits the TGF-βR-1 pathway forabout one to about twelve days. Alternatively, the cells expressingmarkers characteristic of the pancreatic endoderm lineage are treatedwith the factor that inhibits the TGF-βR-1 pathway for about five toabout twelve days. Alternatively, the cells expressing markerscharacteristic of the pancreatic endoderm lineage are treated with thefactor that inhibits the TGF-βR-1 pathway for about twelve days.

Any cell expressing markers characteristic of the pancreatic endodermlineage is suitable for differentiating into a cell expressing markerscharacteristic of the pancreatic endocrine lineage using this method.

In one embodiment, the present invention provides a method fordifferentiating cells expressing markers characteristic of thepancreatic endoderm lineage into cells expressing markers characteristicof the pancreatic endocrine lineage, comprising the steps of:

-   -   a. Culturing cells expressing markers characteristic of the        pancreatic endoderm lineage, and    -   b. Treating the cells with a factor that inhibits the Notch        signaling pathway, and a factor that inhibits the TGF-βR-1        signaling pathway.

The cells expressing markers characteristic of the pancreatic endodermlineage are treated with the factor that inhibits the Notch signalingpathway and the factor that inhibits the TGF-βR-1 pathway for about oneto about twelve days. Alternatively, the cells expressing markerscharacteristic of the pancreatic endoderm lineage are treated with thefactor that inhibits the Notch signaling pathway and the factor thatinhibits the TGF-βR-1 pathway for about five to about twelve days.Alternatively, the cells expressing markers characteristic of thepancreatic endoderm lineage are treated with the factor that inhibitsthe Notch signaling pathway and the factor that inhibits the TGF-βR-1pathway for about twelve days.

Any cell expressing markers characteristic of the pancreatic endodermlineage is suitable for differentiating into a cell expressing markerscharacteristic of the pancreatic endocrine lineage using this method.

In one embodiment, the factor that inhibits the Notch signaling pathwayis a γ-secretase inhibitor. In one embodiment, the γ-secretase inhibitoris1S-Benzyl-4R-[1-(1S-carbamoyl-2-phenethylcarbamoyl)-1S-3-methylbutylcarbamoyl]-2R-hydrozy-5-phenylpentyl]carbamic Acid tert-butyl Ester, also known as L-685,458.

L-685,458 may be used at a concentration from about 0.1 μM to about 100μM. In one embodiment, L-685,458 is used at a concentration of about 90μM. In one embodiment, L-685,458 is used at a concentration of about 80μM. In one embodiment, L-685,458 is used at a concentration of about 70μM. In one embodiment, L-685,458 is used at a concentration of about 60μM. In one embodiment, L-685,458 is used at a concentration of about 50μM. In one embodiment, L-685,458 is used at a concentration of about 40μM. In one embodiment, L-685,458 is used at a concentration of about 30μM. In one embodiment, L-685,458 is used at a concentration of about 20μM. In one embodiment, L-685,458 is used at a concentration of about 10μM.

In one embodiment the factor that inhibits the TGF-βR-1 signalingpathway is an inhibitor of TGF-βR-1 kinase. In one embodiment, theTGF-βR-1 kinase inhibitor is(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine). Inanother embodiment, the TGF-βR-1 kinase inhibitor is[3-(Pyridin-2-yl)-4-(4-quinonyl)]-1H-pyrazole.

The TGF-βR-1 kinase inhibitor may be used at a concentration from about0.1 μM to about 100 μM. In one embodiment, TGF-βR-1 kinase inhibitor isused at a concentration of about 90 μM. In one embodiment, TGF-βR-1kinase inhibitor is used at a concentration of about 80 μM. In oneembodiment, TGF-βR-1 kinase inhibitor is used at a concentration ofabout 70 μM. In one embodiment, TGF-βR-1 kinase inhibitor is used at aconcentration of about 60 μM. In one embodiment, TGF-βR-1 kinaseinhibitor is used at a concentration of about 50 μM. In one embodiment,TGF-βR-1 kinase inhibitor is used at a concentration of about 40 μM. Inone embodiment, TGF-βR-1 kinase inhibitor is used at a concentration ofabout 30 μM. In one embodiment, TGF-βR-1 kinase inhibitor is used at aconcentration of about 20 μM. In one embodiment, TGF-βR-1 kinaseinhibitor is used at a concentration of about 10 μM. In one embodiment,TGF-βR-1 kinase inhibitor is used at a concentration of about 1 μM. Inone embodiment, TGF-βR-1 kinase inhibitor is used at a concentration ofabout 0.1 μM.

Cells expressing markers characteristic of the pancreatic endodermlineage may be treated with at least one other additional factor thatmay enhance the formation of cells expressing markers characteristic ofthe pancreatic endocrine lineage. Alternatively, the at least one otheradditional factor may enhance the proliferation of the cells expressingmarkers characteristic of the pancreatic endocrine lineage formed by themethods of the present invention. Further, the at least one otheradditional factor may enhance the ability of the cells expressingmarkers characteristic of the pancreatic endocrine lineage formed by themethods of the present invention to form other cell types, or improvethe efficiency of any other additional differentiation steps.

The at least one additional factor may be, for example, nicotinamide,members of TGF-β family, including TGF-β1, 2, and 3, serum albumin,members of the fibroblast growth factor family, platelet-derived growthfactor-AA, and -BB, platelet rich plasma, insulin growth factor (IGF-I,II), growth differentiation factor (GDF-5, -6, -8, -10, 11), glucagonlike peptide-I and II (GLP-I and II), GLP-1 and GLP-2 mimetobody,Exendin-4, retinoic acid, parathyroid hormone, insulin, progesterone,aprotinin, hydrocortisone, ethanolamine, beta mercaptoethanol, epidermalgrowth factor (EGF), gastrin I and II, copper chelators such as, forexample, triethylene pentamine, forskolin, Na-Butyrate, activin,betacellulin, ITS, noggin, neurite growth factor, nodal, valporic acid,trichostatin A, sodium butyrate, hepatocyte growth factor (HGF),sphingosine-1, VEGF, MG132 (EMD, CA), N2 and B27 supplements (Gibco,CA), steroid alkaloids such as, for example, cyclopamine (EMD, CA),keratinocyte growth factor (KGF), Dickkopf protein family, bovinepituitary extract, islet neogenesis-associated protein (INGAP), Indianhedgehog, sonic hedgehog, proteasome inhibitors, notch pathwayinhibitors, sonic hedgehog inhibitors, or combinations thereof.

The at least one other additional factor may be supplied by conditionedmedia obtained from pancreatic cells lines such as, for example, PANC-1(ATCC No: CRL-1469), CAPAN-1 (ATCC No: HTB-79), BxPC-3 (ATCC No:CRL-1687), HPAF-II (ATCC No: CRL-1997), hepatic cell lines such as, forexample, HepG2 (ATCC No: HTB-8065), and intestinal cell lines such as,for example, FHs 74 (ATCC No: CCL-241).

Detection of Cells Expressing Markers Characteristic of the PancreaticEndocrine Lineage

Markers characteristic of cells of the pancreatic endocrine lineage arewell known to those skilled in the art, and additional markerscharacteristic of the pancreatic endocrine lineage continue to beidentified. These markers can be used to confirm that the cells treatedin accordance with the present invention have differentiated to acquirethe properties characteristic of the pancreatic endocrine lineage.Pancreatic endocrine lineage specific markers include the expression ofone or more transcription factors such as, for example, NGN-3, NeuroD,Islet-1.

Markers characteristic of cells of the β cell lineage are well known tothose skilled in the art, and additional markers characteristic of the βcell lineage continue to be identified. These markers can be used toconfirm that the cells treated in accordance with the present inventionhave differentiated to acquire the properties characteristic of theβ-cell lineage. β cell lineage specific characteristic include theexpression of one or more transcription factors such as, for example,Pdx1 (pancreatic and duodenal homeobox gene-1), Nkx2.2, Nkx6.1, Isl1,Pax6, Pax4, NeuroD, Hnf1b, Hnf-6, Hnf-3beta, and MafA, among others.These transcription factors are well established in the art foridentification of endocrine cells. See, e.g., Edlund (Nature ReviewsGenetics 3: 524-632 (2002)).

The efficiency of differentiation may be determined by exposing atreated cell population to an agent (such as an antibody) thatspecifically recognizes a protein marker expressed by cells expressingmarkers characteristic of the pancreatic endocrine lineage.Alternatively, the efficiency of differentiation may be determined byexposing a treated cell population to an agent (such as an antibody)that specifically recognizes a protein marker expressed by cellsexpressing markers characteristic of the β cell lineage.

Methods for assessing expression of protein and nucleic acid markers incultured or isolated cells are standard in the art. These includequantitative reverse transcriptase polymerase chain reaction (RT-PCR),Northern blots, in situ hybridization (see, e.g., Current Protocols inMolecular Biology (Ausubel et al., eds. 2001 supplement)), andimmunoassays such as immunohistochemical analysis of sectioned material,Western blotting, and for markers that are accessible in intact cells,flow cytometry analysis (FACS) (see, e.g., Harlow and Lane, UsingAntibodies: A Laboratory Manual, New York: Cold Spring Harbor LaboratoryPress (1998)).

In one aspect of the present invention, the efficiency ofdifferentiation is determined by measuring the percentage of insulinpositive cells in a given cell culture following treatment. In oneembodiment, the methods of the present invention produce about 100%insulin positive cells in a given culture. In an alternate embodiment,the methods of the present invention produce about 90% insulin positivecells in a given culture. In an alternate embodiment, the methods of thepresent invention produce about 80% insulin positive cells in a givenculture. In an alternate embodiment, the methods of the presentinvention produce about 70% insulin positive cells in a given culture.In an alternate embodiment, the methods of the present invention produceabout 60% insulin positive cells in a given culture. In an alternateembodiment, the methods of the present invention produce about 50%insulin positive cells in a given culture. In an alternate embodiment,the methods of the present invention produce about 40% insulin positivecells in a given culture. In an alternate embodiment, the methods of thepresent invention produce about 30% insulin positive cells in a givenculture. In an alternate embodiment, the methods of the presentinvention produce about 20% insulin positive cells in a given culture.In an alternate embodiment, the methods of the present invention produceabout 10% insulin positive cells in a given culture. In an alternateembodiment, the methods of the present invention produce about 5%insulin positive cells in a given culture.

In one aspect of the present invention, the efficiency ofdifferentiation is determined by measuring glucose-stimulated insulinsecretion, as detected by measuring the amount of C-peptide released bythe cells. In one embodiment, cells produced by the methods of thepresent invention produce about 1000 ng C-peptide/pg DNA. In analternate embodiment, cells produced by the methods of the presentinvention produce about 900 ng C-peptide/pg DNA. In an alternateembodiment, cells produced by the methods of the present inventionproduce about 800 ng C-peptide/pg DNA. In an alternate embodiment, cellsproduced by the methods of the present invention produce about 700 ngC-peptide/pg DNA. In an alternate embodiment, cells produced by themethods of the present invention produce about 600 ng C-peptide/pg DNA.In an alternate embodiment, cells produced by the methods of the presentinvention produce about 500 ng C-peptide/pg DNA. In an alternateembodiment, cells produced by the methods of the present inventionproduce about 400 ng C-peptide/pg DNA. In an alternate embodiment, cellsproduced by the methods of the present invention produce about 500 ngC-peptide/pg DNA. In an alternate embodiment, cells produced by themethods of the present invention produce about 400 ng C-peptide/pg DNA.In an alternate embodiment, cells produced by the methods of the presentinvention produce about 300 ng C-peptide/pg DNA. In an alternateembodiment, cells produced by the methods of the present inventionproduce about 200 ng C-peptide/pg DNA. In an alternate embodiment, cellsproduced by the methods of the present invention produce about 100 ngC-peptide/pg DNA. In an alternate embodiment, cells produced by themethods of the present invention produce about 90 ng C-peptide/pg DNA.In an alternate embodiment, cells produced by the methods of the presentinvention produce about 80 ng C-peptide/pg DNA. In an alternateembodiment, cells produced by the methods of the present inventionproduce about 70 ng C-peptide/pg DNA. In an alternate embodiment, cellsproduced by the methods of the present invention produce about 60 ngC-peptide/pg DNA. In an alternate embodiment, cells produced by themethods of the present invention produce about 50 ng C-peptide/pg DNA.In an alternate embodiment, cells produced by the methods of the presentinvention produce about 40 ng C-peptide/pg DNA. In an alternateembodiment, cells produced by the methods of the present inventionproduce about 30 ng C-peptide/pg DNA. In an alternate embodiment, cellsproduced by the methods of the present invention produce about 20 ngC-peptide/pg DNA. In an alternate embodiment, cells produced by themethods of the present invention produce about 10 ng C-peptide/pg DNA.

Therapies

In one aspect, the present invention provides a method for treating apatient suffering from, or at risk of developing, Type 1 diabetes. Thismethod involves culturing pluripotent stem cells, differentiating thepluripotent stem cells in vitro into a β-cell lineage, and implantingthe cells of a β-cell lineage into a patient.

In yet another aspect, this invention provides a method for treating apatient suffering from, or at risk of developing, Type 2 diabetes. Thismethod involves culturing pluripotent stem cells, differentiating thecultured cells in vitro into a (3-cell lineage, and implanting the cellsof a β-cell lineage into the patient.

If appropriate, the patient can be further treated with pharmaceuticalagents or bioactives that facilitate the survival and function of thetransplanted cells. These agents may include, for example, insulin,members of the TGF-β family, including TGF-β1, 2, and 3, bonemorphogenic proteins (BMP-2, -3, -4, -5, -6, -7, -11, -12, and -13),fibroblast growth factors-1 and -2, platelet-tderived growth factor-AA,and —BB, platelet rich plasma, insulin growth factor (IGF-I, II) growthdifferentiation factor (GDF-5, -6, -7, -8, -10, -15), vascularendothelial cell-derived growth factor (VEGF), pleiotrophin, endothelin,among others. Other pharmaceutical compounds can include, for example,nicotinamide, glucagon like peptide-I (GLP-1) and II, GLP-1 and 2mimetibody, Exendin-4, retinoic acid, parathyroid hormone, MAPKinhibitors, such as, for example, compounds disclosed in U.S. PublishedApplication 2004/0209901 and U.S. Published Application 2004/0132729.

The pluripotent stem cells may be differentiated into aninsulin-producing cell prior to transplantation into a recipient. In aspecific embodiment, the pluripotent stem cells are fully differentiatedinto β-cells, prior to transplantation into a recipient. Alternatively,the pluripotent stem cells may be transplanted into a recipient in anundifferentiated or partially differentiated state. Furtherdifferentiation may take place in the recipient.

Definitive endoderm cells or, alternatively, pancreatic endoderm cells,or, alternatively, β cells, may be implanted as dispersed cells orformed into clusters that may be infused into the hepatic portal vein.Alternatively, cells may be provided in biocompatible degradablepolymeric supports, porous non-degradable devices or encapsulated toprotect from host immune response. Cells may be implanted into anappropriate site in a recipient. The implantation sites include, forexample, the liver, natural pancreas, renal subcapsular space, omentum,peritoneum, subserosal space, intestine, stomach, or a subcutaneouspocket.

To enhance further differentiation, survival or activity of theimplanted cells, additional factors, such as growth factors,antioxidants or anti-inflammatory agents, can be administered before,simultaneously with, or after the administration of the cells. Incertain embodiments, growth factors are utilized to differentiate theadministered cells in vivo. These factors can be secreted by endogenouscells and exposed to the administered cells in situ. Implanted cells canbe induced to differentiate by any combination of endogenous andexogenously administered growth factors known in the art.

The amount of cells used in implantation depends on a number of variousfactors including the patient's condition and response to the therapy,and can be determined by one skilled in the art.

In one aspect, this invention provides a method for treating a patientsuffering from, or at risk of developing diabetes. This method involvesculturing pluripotent stem cells, differentiating the cultured cells invitro into a β-cell lineage, and incorporating the cells into athree-dimensional support. The cells can be maintained in vitro on thissupport prior to implantation into the patient. Alternatively, thesupport containing the cells can be directly implanted in the patientwithout additional in vitro culturing. The support can optionally beincorporated with at least one pharmaceutical agent that facilitates thesurvival and function of the transplanted cells.

Support materials suitable for use for purposes of the present inventioninclude tissue templates, conduits, barriers, and reservoirs useful fortissue repair. In particular, synthetic and natural materials in theform of foams, sponges, gels, hydrogels, textiles, and nonwovenstructures, which have been used in vitro and in vivo to reconstruct orregenerate biological tissue, as well as to deliver chemotactic agentsfor inducing tissue growth, are suitable for use in practicing themethods of the present invention. See, for example, the materialsdisclosed in U.S. Pat. Nos. 5,770,417, 6,022,743, 5,567,612, 5,759,830,6,626,950, 6,534,084, 6,306,424, 6,365,149, 6,599,323, 6,656,488, U.S.Published Application 2004/0062753 A1, U.S. Pat. Nos. 4,557,264 and6,333,029.

To form a support incorporated with a pharmaceutical agent, thepharmaceutical agent can be mixed with the polymer solution prior toforming the support. Alternatively, a pharmaceutical agent could becoated onto a fabricated support, preferably in the presence of apharmaceutical carrier. The pharmaceutical agent may be present as aliquid, a finely divided solid, or any other appropriate physical form.Alternatively, excipients may be added to the support to alter therelease rate of the pharmaceutical agent. In an alternate embodiment,the support is incorporated with at least one pharmaceutical compoundthat is an anti-inflammatory compound, such as, for example compoundsdisclosed in U.S. Pat. No. 6,509,369.

The support may be incorporated with at least one pharmaceuticalcompound that is an anti-apoptotic compound, such as, for example,compounds disclosed in U.S. Pat. No. 6,793,945.

The support may also be incorporated with at least one pharmaceuticalcompound that is an inhibitor of fibrosis, such as, for example,compounds disclosed in U.S. Pat. No. 6,331,298.

The support may also be incorporated with at least one pharmaceuticalcompound that is capable of enhancing angiogenesis, such as, forexample, compounds disclosed in U.S. Published Application 2004/0220393and U.S. Published Application 2004/0209901.

The support may also be incorporated with at least one pharmaceuticalcompound that is an immunosuppressive compound, such as, for example,compounds disclosed in U.S. Published Application 2004/0171623.

The support may also be incorporated with at least one pharmaceuticalcompound that is a growth factor, such as, for example, members of theTGF-β family, including TGF-β1, 2, and 3, bone morphogenic proteins(BMP-2, -3, -4, -5, -6, -7,-11, -12, and -13), fibroblast growthfactors-1 and -2, platelet-derived growth factor-AA, and —BB, plateletrich plasma, insulin growth factor (IGF-I, II) growth differentiationfactor (GDF-5, -6, -8, -10, -15), vascular endothelial cell-derivedgrowth factor (VEGF), pleiotrophin, endothelin, among others. Otherpharmaceutical compounds can include, for example, nicotinamide, hypoxiainducible factor 1-alpha, glucagon like peptide-I (GLP-1), GLP-1 andGLP-2 mimetibody, and II, Exendin-4, nodal, noggin, NGF, retinoic acid,parathyroid hormone, tenascin-C, tropoelastin, thrombin-derivedpeptides, cathelicidins, defensins, laminin, biological peptidescontaining cell- and heparin-binding domains of adhesive extracellularmatrix proteins such as fibronectin and vitronectin, MAPK inhibitors,such as, for example, compounds disclosed in U.S. Published Application2004/0209901 and U.S. Published Application 2004/0132729.

The incorporation of the cells of the present invention into a scaffoldcan be achieved by the simple depositing of cells onto the scaffold.Cells can enter into the scaffold by simple diffusion (J. Pediatr. Surg.23 (1 Pt 2): 3-9 (1988)). Several other approaches have been developedto enhance the efficiency of cell seeding. For example, spinner flaskshave been used in seeding of chondrocytes onto polyglycolic acidscaffolds (Biotechnol. Frog. 14(2): 193-202 (1998)). Another approachfor seeding cells is the use of centrifugation, which yields minimumstress to the seeded cells and enhances seeding efficiency. For example,Yang et al. developed a cell seeding method (J. Biomed. Mater. Res.55(3): 379-86 (2001)), referred to as Centrifugational CellImmobilization (CCI).

The present invention is further illustrated, but not limited by, thefollowing examples.

EXAMPLES Example 1

Human Embryonic Stem Cell Culture.

The human embryonic stem cell lines H1, H7 and H9 were obtained fromWiCell Research Institute, Inc., (Madison, Wis.) and cultured accordingto instructions provided by the source institute. Briefly, cells werecultured on mouse embryonic fibroblast (MEF) feeder cells in ES cellmedium consisting of DMEM/F12 (Invitrogen/GIBCO) supplemented with 20%knockout serum replacement, 100 nM MEM nonessential amino acids, 0.5 mMbetamercaptoethanol, 2 mM L-glutamine with 4 ng/ml human basicfibroblast growth factor (bFGF) (all from Invitrogen/GIBCO). MEF cells,derived from E13 to 13.5 mouse embryos, were purchased from CharlesRiver. MEF cells were expanded in DMEM medium supplemented with 10% PBS(Hyclone), 2 mM glutamine, and 100 mM MEM nonessential amino acids.Sub-confluent MEF cell cultures were treated with 10 μg/ml mitomycin C(Sigma, St. Louis, Mo.) for 3 h to arrest cell division, thentrypsinized and plated at 2×10⁴/cm² on 0.1% bovine gelatin-coateddishes. MEF cells from passage two through four were used as feederlayers. Human embryonic stem cells plated on MEF cell feeder layers werecultured at 37° C. in an atmosphere of 5% CO₂ within a humidified tissueculture incubator. When confluent (approximately 5-7 days afterplating), human embryonic stem cells were treated with 1 mg/mlcollagenase type IV (Invitrogen/GIBCO) for 5-10 min and then gentlyscraped off the surface using a 5-ml pipette. Cells were spun at 900 rpmfor 5 min, and the pellet was resuspended and re-plated at a 1:3 to 1:4ratio of cells in fresh culture medium.

Example 2

Differentiation of Human Embryonic Stem Cells Cultured on Tissue CultureSubstrate Coated with MATRIGEL™ to Pancreatic Endocrine Cells.

Cells of the human embryonic stem cell line H1, at passage 45 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days, followed by treatment with DMEM/F12 mediasupplemented with 2% FBS and 100 ng/ml Activin-A (AA) for an additionalthree days. Next the cultures were treated with DMEM/F12+2% FBS+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three daysfollowed by four day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20ng/ml FGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO).

Next, the cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50ng/ml Exendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA) for six daysfollowed by additional three days incubation in DMEM/F12+1% B27(Invitrogen, CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech,NJ)+50 ng/ml HGF (R&D Systems, MN). An outline of the procedure isdepicted in FIGS. 1A-1C. RNA samples were collected from cultures atvarious stages of differentiation. FIG. 2 displays the real-time PCRdata obtained from cells harvested at stages 3 to 5. There was asignificant increase in expression of endocrine markers, such as insulinand glucagon observed in cells at stages 4 and 5, along with an increasein expression of NeuroD.

Example 3

The Effects of Various Compounds on the Expression of MarkersCharacteristic of the Pancreatic Endocrine Lineage in Pluripotent StemCells Treated According to the Differentiation Protocol Outlined in FIG.1A.

Cells of the human embryonic stem cell line H1, at passage 51 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO).

Next, the cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50ng/ml Exendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA) for six daysfollowed by additional three days incubation in DMEM/F12+1% B27(Invitrogen, CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech,NJ)+50 ng/ml HGF (R&D Systems, MN). Some of the cultures were treatedwith 1 μM of the following compounds at either stage 3, stage 4, orstages 3+4: MEK/MAPK inhibitor (2′-Amino-3′-methoxyflavone) (PD98059,Calbiochem, CA), RAF kinase inhibitor(5-Iodo-3-[3,5-dibromo-4-hydroxyphenyl)methylene]-2-indolinone)(#553008, Calbiochem, CA), SMAD3 inhibitor(6,7-Dimethyl-2-((2E)-3-(1-methyl-2-phenyl-1Hpyrrolo[2,3-b]pyridin-3-yl-prop-2-enoyl))-1,2,3,4-tetrahydroisoquinoline)(#566405, Calbiochem, CA), AKT inhibitor(1L6-Hydroxymethyl-chiroinositol-2-(R)-2-O-methyl-3-O-octadecyl-sn-glycerocarbonate)(#124005, Calbiochem, CA), MEK inhibitor (#444937 Calbiochem, CA), andTGF-β receptor I inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine)(inhibits activin receptor-like kinase 5, #616452, Calbiochem, CA).

FIGS. 3A-3E display the real-time PCR data obtained from cell harvestedat the end of stages 3 to 5, treated with the conditions indicated. Notethat addition of the TGF-β receptor I kinase inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) tocells at stage 4 or to cells stages 3 and 4 significantly enhancedexpression of insulin, glucagon, NeuroD, and NKX2.2 while marginallyaffecting the expression of PDX-1 at the end of stage 5. Addition of theTGF-β receptor I kinase inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) only atcells at stage 3 marginally upregulated expression of endocrine markersin cells at the end of stage 5.

Example 4

The Effect of the Addition of TGF-β Receptor I Kinase Inhibitor on theExpression of Markers Characteristic of the Pancreatic Endocrine Lineagein Pluripotent Stem Cells Treated According to the DifferentiationProtocol Outlined in FIG. 1A.

Cells of the human embryonic stem cell line H1, at passage 44 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA) for six days followedby additional three days incubation in DMEM/F12+1% B27 (Invitrogen,CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech, NJ)+50 ng/mlHGF (R&D Systems, MN). Some of the cultures were treated with 1 μM ofTGF-B receptor I kinase inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) (aninhibitor of activin receptor-like kinase 5, #616452, Calbiochem, CA) atstage 4, stage 5, or stages 4 and 5.

FIGS. 4A-4E display the real-time PCR data from cells harvested at theend of stages 3 to 5+/− kinase inhibitor at stages 4 to 5. Note thataddition of the TGF-β receptor I kinase inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) tocells at stage 4 or stages 4 and 5 significantly enhanced expression ofinsulin, glucagon, NeuroD, and NKX2.2 while marginally affectingexpression of PDX-1 at the end of stage 5. Addition of the TGF-βreceptor I kinase inhibitor(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) only atstages 5 marginally upregulated expression of endocrine markers at theend of stage 5.

Example 5

The Effect of Various TGF-β Receptor I Kinase Inhibitors on theExpression of Markers Characteristic of the Pancreatic Endocrine Lineagein Pluripotent Stem Cells Treated According to the DifferentiationProtocol Outlined in FIG. 1A.

Cells of the human embryonic stem cell line H1, at passage 41 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA) for six days followedby additional three days incubation in DMEM/F12+1% B27 (Invitrogen,CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech, NJ)+50 ng/mlHGF (R&D Systems, MN). Some of the cultures were treated with 1-10 μm ofTGF-β receptor I kinase inhibitor (ALK5 inhibitor II)(2-(3-(6-Methylpyridin-2-yl)-1H-pyrazol-4-yl)-1,5-naphthyridine) (aninhibitor of activin receptor-like kinase 5, #616452, Calbiochem, CA) orTGF-β receptor I inhibitor I (ALK5 inhibitor I)([3-(Pyridin-2-yl)-4-(4-quinonyl)]-1H-pyrazole) (#616451, Calbiochem,CA) at stages 4 and 5.

FIGS. 5A-5E display the real-time PCR data from cells harvested at theend of stages 4-5+/− ALK5 inhibitor I or II. Note that addition of theALK5 inhibitor I or II at 1-10 μm to stages 4 and 5 significantlyenhanced expression of insulin, glucagon, PDX-1 and NeuroD, at the endof stages 4 to 5 as compared to controls (standard treatment). All thesamples were in triplicate.

Example 6

The Effect of Noggin and ALK5 Inhibitors on the Expression of MarkersCharacteristic of the Pancreatic Endocrine Lineage in Pluripotent StemCells Treated According to the Differentiation Protocol Outlined in FIG.1A.

Cells of the human embryonic stem cell line H1, at passage 41 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO)+0-500ng/ml of Noggin (R & D Systems, MN).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 um DAPT (Calbiochem, CA)+1 μm ALK5 inhibitor II(Calbiochem, Ca) for six days followed by additional three daysincubation in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/ml Exendin-4(Sigma, MO)+50 ng/ml IGF (Peprotech, NJ)+50 ng/ml HGF (R&D Systems,MN)+1 μM ALK5 inhibitor II.

FIGS. 6A-6G display the real-time PCR data from cells harvested at theend of stages 3-5+/−0-100 ng/ml Noggin. Addition of 100 ng/ml of Nogginat stage 3 marginally enhanced expression of insulin and glucagon at theend of stage 4, while significantly suppressing the expression ofalbumin and CDX2 as compared to untreated samples. Addition of 500 ng/mlof Noggin did not affect expression of PDX-1 but did significantlydiminish expression of endocrine markers, along with albumin and CDX2.Albumin is a marker for liver precursor cells, while CDX2 is marker forgut cells.

Example 7

The Effect of the Addition of Noggin at Stage 3 and ALK5 Inhibitors atStages 4 and 5 on the Expression of Markers Characteristic of thePancreatic Endocrine Lineage in Pluripotent Stem Cells Treated Accordingto the Differentiation Protocol Outlined in FIGS. 1A-1C.

Cells of the human embryonic stem cell line H1, at passage 44 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO)+100ng/ml of Noggin (R & D Systems, MN).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA)+1 μm ALK5 inhibitor II(Calbiochem, Ca)+/−100 ng/ml of Noggin for six days followed byadditional three days incubation in DMEM/F12+1% B27 (Invitrogen, CA)+50ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech, NJ)+50 ng/ml HGF(R&D Systems, MN)+1 μM ALK5 inhibitor II.

FIGS. 7A-7F display the real-time PCR data from cells harvested at theend of stages 4 to 5+/−100 ng/ml Noggin. Addition of 100 ng/ml of Nogginat stage 3+4 plus addition of ALK5 inhibitor II dramatically enhancedexpression of insulin and glucagons at stages 4-5. In particular,addition of Noggin at both stages Sand 4 significantly enhancedexpression of NGN3, an endocrine precursor marker, while significantlysuppressing the expression of albumin and CDX2 as compared to untreatedsamples.

FIGS. 8A-8D depict a phase contrast image of the cultures according tothe above protocol. In some of the cultures, stage 5 was extended from 3days to 21 days. By day 10-12 of culture in stage 5 media, there weredistinct clusters of cells resembling human islets present throughoutthe culture plate. FIGS. 8A-8B show images of day 6 cultures in stage 5while FIGS. 8C-8D show images of day 12 stage 5 cultures. Some of theclusters were manually removed, plated on 1:30 MATRIGEL-coated plates instage 5 media. After 2 days of incubation, the clusters were stained forinsulin and glucagon. The majority of the cells in the clusters as shownin FIGS. 9A-9B were positive for human insulin. In order to furtheroptimize the dose of the BMP inhibitor, Noggin; cultures were treated atstage 2-4 with 0, 10, 50, or 100 ng/ml of Noggin. FIG. 10 depictsexpression of NGN3 at stage 4 for cultures treated with varying doses ofNoggin at stages 2-4. It appears that 50-100 ng/ml of Noggin results inmaximal expression of NGN3 at stage 4.

Example 8

The Effect of the Addition of Noggin at Stages 3-4, Netrin at Stage 4and ALK5 Inhibitors at Stage 4 on the Expression of MarkersCharacteristic of the Pancreatic Endocrine Lineage in Pluripotent StemCells Treated According to the Differentiation Protocol Outlined inFIGS. 1A-1C.

Cells of the human embryonic stem cell line H1, at passage 48 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 2% fatty-acid BSA, and 100 ng/mlActivin-A (R&D Systems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002,R&D Systems, MN), for two days followed by treatment with DMEM/F12 mediasupplemented with 2% BSA and 100 ng/ml Activin-A (AA) for an additionaltwo days. Next the cultures were treated with DMEM/F12+2% FBS+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three daysfollowed by four day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20ng/ml FGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma,MO)+100 ng/ml of Noggin (R & D Systems, MN).

Next, cells were cultured incubation in DMEM/F12+1% B27 (Invitrogen,CA)+50 ng/ml Exendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA)+1 μm ALK5inhibitor II (Calbiochem, Ca)+/−100 ng/ml of Noggin+100 ng/ml Netrin-4for three days.

FIGS. 11A-11F display the real-time PCR data from cells harvested at theend of stage 4+/−100 ng/ml Netrin-4 at stage 4. Addition of 100 ng/ml ofNoggin at stage 3 and 4 plus addition of ALK5 inhibitor II and 100 ng/mlof Netrin-4 at stage 4 dramatically enhanced expression of NGN3, NeuroD,and Pax4 in cells harvested at the end of stage 5.

In some of the stage 4 cultures, Noggin was omitted while Netrin-4 plusAlk5 inhibitor were added. FIGS. 12A-12D show that omission of Noggin atstage 4 did significantly reduce expression of NGN3, NKX2.2, and NeuroDwhile moderately affecting expression of insulin and glucagon in cellsharvested at the end of stage 5.

Example 9

In Vitro Glucose Stimulated Insulin Secretion (GSIS) by Pluripotent StemCells Treated According to the Differentiation Protocol Outlined in FIG.1B.

Cells of the human embryonic stem cell line H1, at passage 48 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 2% fatty-acid BSA, and 100 ng/mlActivin-A (R&D Systems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002,R&D Systems, MN), for two days followed by treatment with DMEM/F12 mediasupplemented with 2% BSA and 100 ng/ml Activin-A (AA) for an additionaltwo days. Next the cultures were treated with DMEM/F12+2% FBS+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three daysfollowed by four day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20ng/ml FGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma,MO)+100 ng/ml of Noggin (R & D Systems, MN).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA)+1 μm ALK5 inhibitor II(Calbiochem, Ca)+/−100 ng/ml of Noggin+100 ng/ml Netrin-4 for six days,followed by additional 3-21 days of incubation in DMEM/F12+1% B27(Invitrogen, CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech,NJ)+50 ng/ml HGF (R&D Systems, MN)+1 μM ALK5 inhibitor II.

Stage 5 cultures at days 6, 8, 12, and 20 were tested for GSIS by 1 hrwash in KREBS buffer (Krebs-Ringer solution: 0.1% BSA, 10 mM HEPES, 5 mMNaHCO₃, 129 mM NaCl, 4.8 mM KCl, 2.5 mM CaCl₂, 1.2 mM KH₂PO₄, 1.2 mMMgSO₄, 5 mM NaHCO₃) at 37° C., followed by 1 hr incubation in KREBSbuffer plus 2 mM D-glucose, and an addition 1 hr incubation in KREBSbuffer plus 20 mM D-glucose. Following each incubation, the supernatantwas removed and frozen at −20° C. for further analysis. Levels ofsecreted C-peptide were assayed using the ultra-sensitive C-peptideELISA (Alpco Diagnostics, Sweden). FIGS. 13A-13C depict the levels ofsecreted human C-peptide in response to an in vitro glucose challenge.Early and intermediate incubation periods in stage 5 did not result insignificant stimulation index (ration of secreted C-peptide at highglucose to low glucose), while samples incubated in stage 5 media for 20days showed robust stimulation in response to glucose. This indicatesthat prolonged exposure to stage 5 media does result in maturation ofclusters, which show evidence of GSIS.

Example 10

The Effect of the Addition of Netrin-1 or Netrin-2 on the Expression ofMarkers Characteristic of the Pancreatic Endocrine Lineage inPluripotent Stem Cells Treated According to the Differentiation ProtocolOutlined in FIG. 1B.

Cells of the human embryonic stem cell line H1, at passage 44 werecultured n MATRIGEL™ coated dishes (1:30 dilution) and exposed toDMEM/F12 medium supplemented with 0.5% FBS, and 100 ng/ml Activin-A (R&DSystems, MN) plus 20 ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems,MN), for two days followed by treatment with DMEM/F12 media supplementedwith 2% FBS and 100 ng/ml Activin-A (AA) for an additional two days.Next the cultures were treated with DMEM/F12+2% PBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO).

Next, cells were cultured in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA) for six days followedby additional three days incubation in DMEM/F12+1% B27 (Invitrogen,CA)+50 ng/ml Exendin-4 (Sigma, MO)+50 ng/ml IGF (Peprotech, NJ)+50 ng/mlHGF (R&D Systems, MN). In some of the cultures 50 ng/ml of Netrin-1 orNetrin-2 (R&D Systems, MN) was added at stage 2-5. FIG. 14 displays thereal-time PCR data from cells harvested at stage 5+/−50 ng/ml ofNetrin-1 or Netrin-2 at stages 2 to 5. Addition of either Netrin-1 orNetrin-2 did significantly upregulate expression of glucagon and insulinin cells harvested at the end of stage 5.

Example 11

An Alternative Method to Induce the Expression of Markers Characteristicof the Definitive Endoderm Lineage.

Cells of the human embryonic stem cell line H1, at passage 48 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and differentiatedto cells expressing markers characteristic of the definitive endodermlineage either by:

-   -   a. Culturing in RPMI medium supplemented with 1% B27 supplement        (Invitrogen, Ca), and 50 ng/ml Activin-A (R&D Systems, MN) plus        1 mM Na Butyrate (Sigma, MO) for one day followed by treatment        with RPMI media supplemented with 1% B27 supplement (Invitrogen,        Ca), and 50 ng/ml Activin-A (R&D Systems, MN) plus 0.5 mM Na        Butyrate (Sigma, MO) for an additional three days, or    -   b. DMEM/F12 medium supplemented with 0.5% PBS, and 100 ng/ml        Activin-A (R&D Systems, MN) plus 20 ng/ml WNT-3a (Catalog        #1324-WN-002, R&D Systems, MN), for two days followed by        treatment with DMEM/F12 media supplemented with 2% FBS and 100        ng/ml Activin-A (AA) for an additional two days.

Next the cultures were treated with DMEM/F12+2% FBS+20 ng/ml FGF7+0.25μm Cyclopamine-KAAD (#239804, Calbiochem, CA) for three days followed byfour day incubation in DMEM/F12+1% B27 (Invitrogen, CA)+20 ng/mlFGF7+0.25 μm Cyclopamine-KAAD+2 μm Retinoic acid (RA) (Sigma, MO). Nextcells were incubated in DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/mlExendin-4 (Sigma, MO)+1 μm DAPT (Calbiochem, CA)+1 um ALK5 inhibitor II(Calbiochem, Ca) for three days.

Induction of cultures to definitive endoderm using alternative method a)above resulted in a 78% expression of CXCR4 as measured by FACS, ascompared to 56% CXCR4 expression by alternative method b) above. CXCR4is regarded as a marker for definitive endoderm cells.

FIGS. 15A-15F display the real-time PCR data from cells harvested at theend of stage 5 using either alternative method a) or b). It appears thatalternative method a) can also be used to induce expression ofpancreatic endoderm and endocrine markers.

Example 12

Differentiation of Human Embryonic Stem Cells Cultured in the Absence ofSerum, on Tissue Culture Substrate Coated with MATRIGEL™ to PancreaticEndocrine Cells.

Cells of the human embryonic stem cell line H1, at passage 52 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and exposed toexposed to RPMI medium supplemented with 2% BSA (Catalog #152401, MPBiomedical, Ohio), and 100 ng/ml activin A (R&D Systems, MN) plus 20ng/ml WNT-3a (Catalog #1324-WN-002, R&D Systems, MN) plus 8 ng/ml ofbFGF (Catalog #100-18B, PeproTech, NJ), for one day, followed bytreatment with RPMI media supplemented with 2% BSA and 100 ng/ml activinA plus 8 ng/ml of bFGF for an additional two days. Next the cultureswere treated with DMEM/F12+2% BSA+50 ng/ml FGF7+0.25 μm Cyclopamine-KAAD(#239804, Calbiochem, CA) for two days, followed by four days incubationin DMEM/F12+1% B27 (Invitrogen, CA)+50 ng/ml FGF7+0.25 μmCyclopamine-KAAD+2 μM retinoic acid (RA) (Sigma, MO)+100 ng/ml of Noggin(R & D Systems, MN). Next, the cells were incubated in DMEM/F12+1% B27(Invitrogen, CA)+100 ng/ml Noggin+1 μm DAPT (Catalog #565784,Calbiochem, CA)+1 μm ALK5 inhibitor II (Catalog #616452, Calbiochem,Ca)+100 ng/ml of Netrin-4 (R&D Systems, MN) for three days, followed byadditional seven days incubation in DMEM/F12+1% B27 (Invitrogen, CA)+1μm ALK5 inhibitor II (Calbiochem, Ca). A last stage was added to furthermature the endocrine cultures, which consisted of seven day treatment inDMEM/F12+1% B27 (Invitrogen, CA). Except for the last stage, all otherstages included daily media changes. An outline of the procedure isdepicted in FIG. 1C. At each stage cell number was calculated using ahemocytometer and RNA was collected for PCR analysis. All samples werecollected in triplicate.

FIGS. 16A-16B display the CXCR4 expression as measured by FACS andreal-time PCR data for stage 1 at day 3. Fold change in expression isshown relative to undifferentiated H1 ES cells. FIGS. 16C-16N depictreal-time PCR data for key pancreatic and endocrine markers in cellsharvested at the end of stages 2-6. FIG. 17 depicts the number of cellsat the end of stages 1-6.

Example 13

C-Peptide and Pro-Insulin Content in Pluripotent Stem Cells TreatedAccording to the Differentiation Protocol Outlined in FIG. 1C.

Cells of the human embryonic stem cell line H1, at passage 42 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and differentiatedaccording to the protocol outlined in FIG. 1C, as described in Example12 above.

The cells were washed in Krebs-Ringer buffer (129 mM NaCl, 4.8 mM KCl,1.2 mM NaH₂PO₄, 1.2 mM MgSO₄, 2.5 MM CaCl₂, 5 mM NaHCO₃, 10 mM HEPES,0.3% (wt/vol) BSA) and incubated with the Krebs buffer for 15 minsfollowed by 45 mins incubation in Krebs buffer spiked with 2 mMD-glucose at 37° C., 5% CO₂, 95% Air. 0.5 ml of supernatant wascollected and the remaining media was aspirated and replaced with Krebsbuffer spiked with one of the following stimuli: 20 mM D-glucose (HG),30 mM KCl, 100 μM tolbutamide (tol), 100 mM IBMX, 2 μM BAY K8644, or 10mM ketoisocaproic acid (KIC) for 45 mins at 37° C., 5% CO₂, 95% Air. 0.5ml of supernatant was collected and the remaining media was discarded.The supernatants were analyzed for human C-peptide content usingC-peptide ELISA kit (Catalog #80-CPTHU-E01, Alpco Diagnostics, NH). Thesamples had to be routinely diluted 5-10 fold to fall within the linearrange of the standards provided in the kit.

FIG. 18 shows the C-peptide release following stimulation with variousstimuli. Stimulation index (C-peptide concentration in stimulationsupernatant divided by C-peptide concentration in basal supernatantcontaining 2 mM glucose) for each agent is also shown on the graph.

In order to measure the C-peptide, Pro-insulin, and DNA contents ofstage 6 cultures, 6-well plates containing stage 6 cultures were treatedwith 500 μl of cell lysis buffer per well (10 mM Tris-HCL+1 mM EDTA, pH7.5) followed by 30 sec sonication. C-peptide content and Pro-insulincontent were measured using C-peptide ELISA kit (Catalog #80-CPTHU-E01,Alpco Diagnostics, NH) and Pro-insulin ELISA kit (Catalog #11-1118-01,Alpco Diagnostics, NH), respectively. DNA content of the lysates wasquantified using Quant-IT™ DNA kit (Catalog #P7589, Invitrogen, Ca). Thesamples had to be routinely diluted 500-1000 fold to fall within thelinear range of the standards provided in the kits. FIG. 19 shows theC-peptide content and pro-insulin content normalized to DNA for threedifferent wells of a 6-well plate containing stage 6 cultures. Ascomparison, C-peptide and pro-insulin contents of three different adulthuman cadaver islet samples were also measured. Note that the datareflects the insulin content of the entire culture and not only theclusters present in the culture.

Example 14

FACS Analysis of Pluripotent Stem Cells Treated According to theDifferentiation Protocol Outlined in FIG. 1C.

Cells of the human embryonic stem cell line H1, were cultured onMATRIGEL™ coated dishes (1:30 dilution) and differentiated according tothe protocol outlined in FIG. 1C, as described in Example 12 above.Cells were dissociated into single cells from monolayer cultures usingTrypLE Express (Invitrogen, Carlsbad, Calif.) and washed in cold PBS.For fixation, cells were resuspended in 200-300 μl Cytofix/CytopermBuffer (BD 554722, BD, Ca) and incubated for 30 min at 4° C. Cells werewashed two times in 1 ml Perm/Wash Buffer Solution (BD 554723) andresuspended in 100 μl staining/blocking solution containing 2% normalgoat serum in Perm/Wash buffer. For flow cytometric analysis, cells werestained with the following primary antibodies: Anti-Insulin (Rabbit mAb,Cell Signaling No. C27C9; 1:100 dilution), Anti-Glucagon (Mouse Mab,Sigma No. G2654, 1:100); Anti-Synaptophysin (Rabbit Polyclonal antibody,DakoCytomation No A0010, 1:50); Cells were incubated for 30 min at 4° C.followed by two washes in Perm/Wash buffer and further 30 min incubationin appropriate secondary antibodies as follows: Goat anti-Rabbit Alexa647 (Invitrogen No. A21246) or Goat anti-Mouse 647 (Invitrogen No.A21235); Goat anti-Rabbit R-PE (BioSource No. ALI4407). All secondaryantibodies were used at 1:200 dilution. Cells were washed at least oncein Perm/Wash buffer and analyzed using BD FACSArray. A least 10,000events were acquired for analysis. Controls included undifferentiated H1cells and b-TC (ATCC, VA) cell line. FIGS. 20A-20C show the percentageinsulin positive and synapthophysin+ cells in stage 6 cultures.

Example 15

Addition of Chordin at Stages 3 and 4 of the Differentiation ProtocolOutlined in FIG. 1C Up-Regulate the Expression of Markers Characteristicof the Pancreatic Endocrine Lineage.

Cells of the human embryonic stem cell line H1, at passage 52 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and differentiatedaccording to the protocol outlined in FIG. 1C, with the exception thatthat 50-100 ng/ml of Chordin (R&D Systems, MN) was added to stages 3-4instead of Noggin. Similar to Noggin, Chordin is also a known inhibitorof BMP signaling. Analysis of stage 6 cultures by FACS (FIGS. 21A-21B)revealed very similar expression of insulin and synaptophysin asobserved with addition of Noggin at stages 3-4.

Example 16

Differentiation of Human Embryonic Stem Cells Cultured in the Absence ofSerum, on Tissue Culture Substrate Coated with MATRIGEL™ to PancreaticEndocrine Cells.

Cells of the human embryonic stem cell line H9, at passage 39 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and differentiatedaccording to the protocol outlined in FIG. 1C, as described in Example12 above. RNA was collected at the end of stages 1-6. FIGS. 22A-22Ldepict real-time PCR data for key pancreatic and endocrine markersharvested at the end of stages 3-6. Similar to results obtained with H1line, H9 cells were able to express markers characteristic of thepancreatic endocrine lineage.

Example 17

The Effect of Media Supplements on the Ability of pluripotent Stem Cellsto Differentiate into Pancreatic Endocrine Cells.

Cells of the human embryonic stem cell line H1, at passage 39 werecultured on MATRIGEL™ coated dishes (1:30 dilution) and differentiatedaccording to the protocol outlined in FIG. 1C, with the exception thatin some cultures, DMEM/F12 basal media was supplemented with 0.25-1% B27or 1% N2 (Invitrogen, Ca)+2% BSA. All other components of thedifferentiation protocol were kept as outlined in Example 12. Sampleswere collected in triplicate at the end of stages 3, 5 and 6 andanalyzed by real-time PCR. FIGS. 23A-D depict real-time PCR data for keypancreatic and endocrine markers from cells harvested at the end ofstages 3, 5, and 6. Use of N2/BSA as a replacement for B27 resulted invery similar expression of key pancreatic endocrine markers.Furthermore, concentration of B27 could be lowered to 0.25% withoutsignificantly affecting expression of key pancreatic endocrine markers.

Publications cited throughout this document are hereby incorporated byreference in their entirety. Although the various aspects of theinvention have been illustrated above by reference to examples andpreferred embodiments, it will be appreciated that the scope of theinvention is defined not by the foregoing description but by thefollowing claims properly construed under principles of patent law.

1. A composition, comprising human pancreatic endoderm cells, humanpancreatic endocrine cells, and an effective amount of noggin and anALK5 inhibitor, wherein the noggin and the ALK5 inhibitor differentiatethe human pancreatic endoderm cells into human pancreatic endocrinecells.
 2. The composition of claim 1, wherein the ALK5 inhibitor is ALK5inhibitor I.
 3. The composition of claim 1, wherein the ALK5 inhibitoris ALK5 inhibitor II.
 4. The composition of claim 1, wherein there aremore human pancreatic endocrine cells than human pancreatic endodermcells in the composition.
 5. The composition of claim 1, wherein thehuman pancreatic endoderm cells and/or the human pancreatic endocrinecells are derived from human embryonic stem cells.
 6. The composition ofclaim 1, wherein the human pancreatic endocrine cells express at leastone of: NGN-3, NeuroD, Islet-1, PDX-1, PAX-4, and NKX2.2.
 7. Thecomposition of claim 1, wherein the human pancreatic endocrine cells areβ-cells.
 8. The composition of claim 1, wherein the human pancreaticendocrine cells express at least one of: H1xb9, PTF-1a, PDX-1, HNF-6,and HNF-1beta.
 9. The composition of claim 1, wherein the noggin ispresent in the composition at a concentration of about 500 ng/ml toabout 500 μg/ml.
 10. The composition of claim 1, wherein the ALKinhibitor is present in the composition at a concentration of about 1 μMto about 10 μM.